CN107621693B - Laser stroboscopic illumination device for optical microscopy - Google Patents

Abstract

The application discloses a laser stroboscopic lighting device for an optical microscope, which comprises a laser diode, a lens barrel for fixing the laser diode, a fixing bracket connected with the microscope, a driving circuit of the laser diode and a power supply. The laser diodes emit pulse light at the same time interval, and illuminate the sample to be detected on the object stage in a certain direction, so that the illumination uniformity is improved, the laser speckles are weakened, the illumination is improved, the resolution of the microscope is improved, and the laser speckles in the field of view can be effectively restrained by adjusting the direction and the angle of the incident light.

Description

Laser stroboscopic illumination device for optical microscopy

Technical field

The invention belongs to the field of illumination, and in particular relates to a device for laser stroboscopic illumination of an optical microscope.

Background technique

In optical microscopy, illumination devices are essential. In order to improve the quality of imaging and observe clear pictures, auxiliary lighting equipment must be added to the microscope. In the existing technology, an auxiliary light source is mainly used to illuminate the sample to be tested, or ambient light is collected and used to illuminate the sample to be tested. Commonly used auxiliary light sources are LED lamps, low-voltage tungsten lamps, halogen lamps, xenon lamps and ultra-high-pressure mercury lamps.

These lamps cannot meet the lighting requirements of modern microscopes. In order to improve the resolution of the microscope, short-wavelength lighting sources must be used. However, the wavelength range of the light sources in existing technical solutions is generally wider and contains components with larger wavelengths, which is not conducive to the microscope. Resolution improvement. In order to limit the wavelength of the light source, color filters are usually used. However, after using color filters, the illumination on the sample to be observed will decrease significantly. In order to meet the illumination requirements, the power of the light source must be increased, which increases power consumption, causes heat dissipation difficulties, shortens the life of the light source, and increases costs.

Modern microscopes are usually equipped with various shooting devices to convert pictures of the object to be measured into electrical signals and store them in various memories. In order to photograph objects that move or change at high speed relative to the microscope lens, the exposure time is often required to be short enough to obtain a clear image. However, the existing optical shutter can only reach 1/8000 second, which cannot meet the requirements of shooting fast-changing objects. In existing shooting devices, CCD (Charge Coupled Device) is usually used as the photosensitive element. The charge accumulation time on the CCD surface can be controlled through the electronic shutter to control the exposure time. The exposure time is usually between 1/60 second and 1/10000 second. Within the range, the exposure time of 1/10000 seconds still cannot meet the requirements for shooting high-speed changing objects, and because the exposure time is very short, there are few photons falling on the CCD, and the collected images are very dark. Even if various algorithms can be used to improve The brightness of the image is good, but the signal-to-noise ratio of the image is not good and the image is not clear. In order to increase the number of photons, the brightness of the light source needs to be increased dozens or even hundreds of times. However, existing microscope illumination sources cannot meet this requirement.

Existing strobe lights are large in size, have high power consumption, and their frequency and brightness cannot meet the requirements.

The existing microscope light source needs to focus the light on the surface of the object to be measured, so it requires auxiliary structures such as mirrors or lenses, which results in a larger volume and higher processing costs.

Existing microscope light sources have the following technical problems: the light emitted by the light source contains components with longer wavelengths, which limits the resolution of the microscope; in order to use monochromatic light with shorter wavelengths, color filters are required, resulting in a decrease in illumination; brightness It is not tall enough to meet the requirements for shooting rapidly changing objects; it generates a lot of heat, is difficult to dissipate heat, and has a short service life; it cannot cooperate well with the CCD in the shooting device; it is large in size and has high processing costs.

Contents of the invention

In order to solve the above problems, the present invention discloses a laser stroboscopic illumination device for optical microscopes, which includes a laser diode, a lens barrel, a lens, a fixed bracket, a drive circuit, and a power supply; the lens barrel is composed of a fixed sleeve and a fixed base Composed of: the fixed sleeve is mechanically connected to the fixed base; the laser diode is mechanically connected to the fixed base; the lens is mechanically connected to the fixed sleeve; the lens barrel It is mechanically connected to the fixed bracket, which is installed near the objective lens of the microscope; the laser diode is electrically connected to the drive circuit, and the drive circuit is connected to the power supply; the fixed bracket It has two parts: a mounting end and a lens barrel bracket; the mounting end is an annular structure, and the mounting end has threads; the lens barrel bracket is composed of a fixed ring, a ring, a plurality of transverse extension ends, and a longitudinal bracket. ; The fixed ring is mechanically connected to the circular ring, the circular ring is mechanically connected to the transversely extending end, and the transversely extending end is mechanically connected to the longitudinal bracket; adjacent The angles between the transverse extension ends are equal, each longitudinal bracket has a mounting hole, and the fixing ring is mechanically connected to the mounting end; the drive circuit supplies power to multiple laser diodes at the same time, and the multiple laser diodes are powered from the The sample being observed is illuminated in different directions.

Preferably, a piezoelectric ceramic piece is installed at the rear end of the lens barrel.

Preferably, the mounting end is made of plastic material.

Preferably, there are screws at the end of the fixing sleeve, and the lens barrel is fixed on the lens barrel bracket through the screws.

The beneficial effects of the present invention are: the wavelength of the light source is single and the wavelength is short, which can significantly improve the resolution of the microscope; there is no need to use color filters and the illumination will not be reduced; the brightness of the light source is large enough to meet the rapid changes in microscope photography. Object requirements; low heat generation and long service life; can well cooperate with the CCD in the shooting device; small size and low processing cost.

The present invention uses a stroboscopic lighting device composed of a laser diode, a lens barrel, a lens, a fixed bracket, a driving circuit, and a power supply to generate pulse laser beam illumination. The duration of the pulse laser can be much shorter than the shutter time, which can improve the efficiency of microscope imaging. The time resolution meets the requirements for shooting rapidly changing objects; the lens barrel is fixed on the lens barrel bracket through screws, and the angle of incident light can be adjusted according to lighting needs; the structure is simple, easy to install and disassemble, and reduces costs.

Description of drawings

The present invention will be further described in detail below in conjunction with the accompanying drawings and examples. The drawings are used to provide a further understanding of the present invention and are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation of the present invention.

Figure 1 is a schematic diagram of the fixing bracket and lens barrel in the embodiment.

Figure 2 is a schematic structural diagram of the lens barrel bracket of the embodiment.

Figure 3 is a schematic structural diagram of the lens barrel of the embodiment.

Figure 4 is a partial structural diagram of the embodiment.

In the picture: 1. Installation end, 2. Lens tube bracket, 3. Lens tube, 4. M3 screw hole, 21. Fixing ring, 22. Ring, 23. Lateral extension end, 24. Longitudinal bracket, 31. Fixed sleeve, 32. Fixed base, 33. Lens, 34. Laser diode, 35. Piezoelectric ceramics, 36. Screws.

Detailed ways

The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. The following embodiments are only exemplary and can only be used to explain and illustrate the technical solutions of the present invention, but cannot be interpreted as limiting the technical solutions of the present invention.

In the figure, a laser stroboscopic illumination device for an optical microscope includes a laser diode, a lens barrel, a lens, a fixed bracket, a drive circuit, and a power supply; the lens barrel is composed of a fixed sleeve and a fixed base, and the The fixed sleeve is mechanically connected to the fixed base; the laser diode is mechanically connected to the fixed base; the lens is mechanically connected to the fixed sleeve; the lens barrel is mechanically connected to the fixed base. The bracket is mechanically connected, and the fixed bracket is installed near the objective lens of the microscope; the laser diode is electrically connected to the drive circuit, the drive circuit is connected to the power supply, and the fixing ring is connected to the installation end Mechanical connection; this application has simple structure, low processing cost, small size, and is easy to install and disassemble.

The fixed bracket is composed of a mounting end and a lens barrel bracket for fixing the laser diode. The mounting end is mechanically connected to the microscope objective or the microscope barrel. The mounting end has a circular structure. The upper inner surface of the mounting end is provided with threads, and the lower end outer surface is provided with threads. Has threads. The height of the mounting end is 12 mm, and the thread on the inner surface of the upper end of the mounting end is M24, which can match the external thread on an industrial microscope barrel. In Figure 1, there are also horizontal M3 screw holes on the mounting end. The M3 screws alone can be used to fix the mounting end to the microscope barrel or objective lens. It is suitable for industrial microscope barrels without external threads. The thread on the outer surface of the lower end of the installation end is M32, which matches the internal thread of the fixed ring. The installation end is made of plastic material. Plastic material is simple to process and has low manufacturing cost. At the same time, plastic material is softer than the metal material of the microscope and will not cause damage to the microscope. The lens barrel bracket consists of a fixed ring, a circular ring, multiple transverse extensions and a longitudinal bracket. The outer diameter of the fixed ring is 39 mm and the height is 5 mm. There are M32 threads inside the fixed ring. The retaining ring is made of plastic material.

In Figure 2, the fixed ring is mechanically connected to the circular ring, the circular ring is mechanically connected to the transversely extending end, and the transversely extending end is mechanically connected to the longitudinal bracket. ; The angles between adjacent transversely extending ends are equal. The longitudinal bracket is at the bend of the outer end of the transversely extending end. Each longitudinal bracket is provided with a "-" shaped mounting hole. , the lens barrel bracket is mechanically connected to the installation end through a fixed ring. The inner diameter of the ring of the lens barrel bracket is 33 mm and the outer diameter is 39 mm. The ring and the fixed ring on the mounting end are bonded with glue. The length of the lateral extension is 18.75 mm and the width is 3.5 mm. The longitudinal bracket is at the bend of the outer end of the transverse extending end, and the angle between the plane where the longitudinal bracket is located and the plane where the transverse extending end is located forms an angle of 90 degrees. The length of the longitudinal bracket is 35 mm and the width is 7 mm. There is a "1"-shaped mounting hole in the longitudinal bracket. The length of the mounting hole is 29 mm and the width is 3 mm. The distance between the mounting hole and the top of the longitudinal bracket is 4 mm. Installation The distance between the hole and the side of the longitudinal bracket is 2 mm. The ring, transverse extension and longitudinal bracket are an integrated structure, all made of 1 mm stainless steel plate. The processing technology of thin steel plate is mature and the processing cost is low, which can effectively reduce the cost of the lens barrel bracket. The fixing ring is mechanically connected to the installation end, and the lens barrel bracket is mechanically connected to the installation end through the fixing ring.

In Figure 3, the diameter of the lens barrel is 8 mm and the length is 10 mm. The length of the tail of the fixed sleeve of the lens barrel is set to 5 mm. The thread is an M3 screw. The lens barrel is fixed on the lens barrel bracket through screws. In Figure 4, the lens barrel is screwed together with nuts through the mounting holes on the longitudinal bracket through screws, and is fixed on the longitudinal bracket. By tightening the nut, the height and irradiation angle of the laser diode can be easily adjusted so that the laser beam is concentrated in the circular field of view of the microscope and irradiates the sample to be measured at a certain angle. In Figures 1 and 2, the lens barrel bracket and the mounting end are connected through threads. The lens barrel bracket has a centerline and can rotate around the centerline, allowing the laser diode to illuminate the sample from different directions. For some samples, it is necessary to use light illumination at a specific angle or direction to clearly display the subtle structure and achieve good shooting effects. This application effectively solves the problem of adjusting the angle and direction of incident light. In some cases, adjusting the angle and direction of the incident light can also weaken or even eliminate laser speckles in the field of view. The structure disclosed in this application helps eliminate speckles and improve the shooting effect.

The mounting end and the lens tube bracket are connected through threads. The height of the lens tube bracket can be adjusted without changing the position of the mounting end. It is also possible to easily adjust the convergence position of the beam emitted by the laser diode when the lens tube is fixed at a good angle. The height enables the beam to accurately converge on the surface of the sample to be measured.

In the embodiment, a piezoelectric ceramic piece is installed at the tail of the lens barrel. By applying AC voltage to the piezoelectric ceramic piece, the vibration of the piezoelectric ceramic causes the laser diode to vibrate, reducing the contrast of the speckle pattern and weakening the laser scattering. The effect of spots on the quality of images taken by a microscope.

The drive circuit supplies power to multiple laser diodes at the same time, and the multiple laser diodes illuminate the observed sample from different directions at the same time. The drive circuit can receive an external pulse voltage signal as a trigger signal. When there is no trigger signal, the current output by the drive circuit is less than the threshold current of the laser diode, and the laser diode does not generate laser light; when there is a trigger signal, the current output by the drive circuit is greater than the laser diode. The threshold current of a diode that generates laser light from a laser diode. Since there are multiple lens tubes and laser diodes on the lens tube holder, multiple laser diodes are used for simultaneous illumination, which increases the uniformity of illumination and improves the illumination brightness. The spots generated by each laser diode overlap each other and weaken the laser speckle. The laser light emitted by each laser diode is incoherent with each other. After superposition, the overall coherence is reduced, which will significantly reduce the intensity of the speckle.

In the embodiment, when the laser diode is stimulated to emit, the working current changes continuously. The continuous change of the working current will cause the wavelength of the emitted laser to change continuously, thereby reducing the coherence of the light and improving the imaging quality; the continuous change of the working current will cause the PN junction to change. The continuous changes in temperature and/or the continuous changes in the resonant cavity further reduce the coherence of light. In one embodiment, the operating current of the laser diode is a triangular wave. In another embodiment, the capacitor discharges the laser diode. The current is maximum at the beginning of each pulse, and then the current continuously decreases. In the third embodiment, the current in each pulse is The capacitor is charged via the laser diode.

In the embodiment, the laser diode is a blue laser diode with a wavelength of 450 nm. The laser tube has small size, long life and small divergence angle. The optical output power is 80 milliwatts at an operating voltage of 5V, and multiple laser diodes light up and extinguish at the same time. The duration of each laser pulse width is 1 microsecond, which is much shorter than the shutter time. When the laser pulse disappears, even if the shutter is still open, there is no light and the CCD will not continue to be exposed to light, which meets the requirements for shooting rapidly changing objects; due to the laser The directionality is good, the light is concentrated on the sample area on the stage, and less light is wasted, which achieves the purpose of energy saving, and does not require a reflector, which reduces the production cost, making maintenance more convenient and low maintenance cost; due to the high brightness of the laser and It is easy to adjust the laser intensity. Each light pulse has enough photons falling on the CCD. The captured image is clear and the signal-to-noise ratio is good. Since the wavelength of the laser is 450nm, there is no light of other wavelengths. Compared with white light illumination, , the resolution of the microscope has also been improved; because no color filter is used, the light utilization of the system is improved, and the overall light utilization of the laser diode is also improved. And due to the use of pulse illumination, the average power of the laser diode is lower. There is no need to use a heat dissipation device, which simplifies the mechanical structure and circuit structure, reduces costs, and reduces the failure rate.

The preferred embodiments of the invention are given in the description of the invention and the accompanying drawings. However, the above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still make various modifications to the foregoing embodiments. The technical solutions described in the embodiments are modified, or some of the technical features are replaced with equivalents. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims (4)

1. Laser strobe lighting device for optical microscopes, which is characterized by: including a laser diode, a lens barrel, a lens, a fixed bracket, a drive circuit, and a power supply; the lens barrel is composed of a fixed sleeve and a fixed base, so The fixed sleeve is mechanically connected to the fixed base; the laser diode is mechanically connected to the fixed base; the lens is mechanically connected to the fixed sleeve; the lens barrel is mechanically connected to the fixed base. The fixed bracket is mechanically connected, and the fixed bracket is installed near the objective lens of the microscope; the laser diode is electrically connected to the drive circuit, and the drive circuit is connected to the power supply; the fixed bracket has an installation end and the lens tube bracket are two parts; the mounting end is a circular structure, and the mounting end has threads; the lens tube bracket is composed of a fixed ring, a ring, a plurality of transverse extension ends and a longitudinal bracket; The fixed ring is mechanically connected to the circular ring, the circular ring is mechanically connected to the transversely extending end, the transversely extending end is mechanically connected to the longitudinal bracket; the adjacent transversely protruding end The angles between the ends are equal, each longitudinal bracket has a mounting hole, and the fixing ring is mechanically connected to the mounting end; the drive circuit supplies power to multiple laser diodes at the same time, and the multiple laser diodes move from different directions at the same time. Illuminate the sample being observed. 2. The laser stroboscopic illumination device for optical microscopes according to claim 1, characterized in that a piezoelectric ceramic sheet is installed at the tail of the lens barrel. 3. The laser stroboscopic illumination device for optical microscope according to claim 1, characterized in that the mounting end is made of plastic. 4. The laser stroboscopic illumination device for optical microscopes according to claim 1, characterized in that there are screws at the tail of the fixed sleeve, and the lens barrel is fixed on the lens barrel bracket through screws.