Laser stroboscopic illumination device and method for optical microscope

Technical field of laser strobe lighting device and method for optical microscope

[0001] The present invention belongs to the field of illumination, and in particular relates to a device and method for laser strobe illumination using an optical microscope.

Background technique

[0002] In an optical microscope, an illumination device is indispensable. In order to improve the quality of imaging and observe clear pictures, auxiliary lighting equipment must be added to the microscope. In the prior art, 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-pressure hook filament lamps, halogen lamps, magic emanation lamps and ultra-high pressure mercury lamps.

[0003] These lamps cannot meet the lighting requirements of modern microscopes. In order to improve the resolution of the microscope, a short-wavelength illuminating light source must be used. However, in the existing technical solutions, the wavelength range of the light source is generally wider and contains components with larger wavelengths. It is not conducive to the improvement of microscope resolution. In order to limit the wavelength of the light source, a color filter is usually used. However, after the color filter is used, the illuminance on the sample to be observed will be significantly reduced. In order to meet the requirements of illuminance, it is necessary to increase the power of the light source, which increases the power consumption, causes difficulty in heat dissipation, shortens the life of the light source, and increases the cost.

[0004] Modern microscopes are usually equipped with various shooting devices to convert pictures of objects to be measured into electrical signals and store them in various memories. In order to photograph objects that move or change at a 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 for shooting high-speed changing objects. In existing imaging devices, CCD (Charge Coupled Element) is usually used as the photosensitive element. The charge accumulation time on the surface of the CCD can be controlled by an electronic shutter to control the exposure time. The exposure time is usually 1/60 second to 1/10000 second. Within the range, the exposure time of 1/10000 second still cannot meet the requirements of shooting high-speed changing objects, and because the exposure time is very short, the photons falling on the CCD are few, and the collected images are very dark, even if various algorithms can be used to improve The brightness of the image, 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, it is necessary to increase the brightness of the light source by tens of times or even hundreds of times. However, the existing microscope illumination light sources cannot meet this requirement.

[0005] The existing stroboscopic lamp has large volume, high power consumption, and the frequency and brightness cannot meet the requirements.

[0006] The existing microscope light source needs to converge the light on the surface of the object to be measured, and therefore requires auxiliary structures such as a reflector or a lens, which results in a larger volume and a higher processing cost.

[0007] The existing microscope light source has 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 a shorter wavelength, a color filter is required, resulting in illuminance Decrease; the brightness is not high enough to meet the requirements of shooting fast-changing objects; the heat generation is large, the heat dissipation is difficult, and the service life is short; it does not work well with the CCD in the shooting device; the volume is large, and the processing cost is high.

Summary of the invention

[0008] In order to solve the above problems, the present invention discloses a laser strobe lighting device and method for an optical microscope, including a laser diode, a lens barrel, a lens, a fixing bracket, a drive circuit, and a power supply; the lens barrel is fixed by The sleeve and the fixed base are composed, the fixed sleeve is mechanically connected to the fixed base; the laser diode is mechanically connected to the fixed base, and the lens is mechanically connected to the fixed sleeve; The lens barrel and the fixing bracket

Mechanically connected, 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 a mounting end and a lens barrel The bracket has two parts; the mounting end is a circular ring structure, and the mounting end is threaded; the lens barrel bracket is composed of a fixing ring, a circular ring, a plurality of laterally extending ends and a longitudinal bracket; the fixing ring It is mechanically connected to the circular ring, the circular ring is mechanically connected to the laterally projecting end, and the laterally projecting end is mechanically connected to the longitudinal support; between adjacent laterally projecting ends The included angles are equal, each longitudinal bracket has a mounting hole, and the fixing ring is mechanically connected to the mounting end; the driving circuit supplies power to multiple laser diodes at the same time, and multiple laser diodes illuminate the light from different directions at the same time. Observed sample.

[0009] Preferably, a piezoelectric ceramic sheet is installed at the tail of the lens barrel.

[0010] Preferably, the mounting end is made of plastic.

[0011] Preferably, there are screws at the end of the fixing sleeve, and the lens barrel is fixed on the lens barrel holder by the screws.

[0012] The beneficial effects of the present invention are: the wavelength of the light source is single, and the wavelength is shorter, which can significantly improve the resolution of the microscope; no color filter is required, and the illuminance will not be reduced; the brightness of the light source is large enough to satisfy the microscope The requirements for shooting fast-changing objects; low heat generation and long service life; it can be well matched with the CCD in the shooting device; the volume is small and the processing cost is low.

[0013] 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 pulsed laser beam illumination. The duration of the pulsed laser can be much shorter than the shutter time, which can increase The time resolution of the microscope imaging meets the requirements of shooting fast-changing objects; the lens barrel is fixed on the lens barrel bracket by screws, and the angle of the incident light can be adjusted according to the lighting needs; the structure is simple, easy to install and disassemble, and reduces the cost.

Description of the drawings

[0014] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The accompanying drawings are used to provide a further understanding of the present invention, and together with the embodiments of the present invention are used to explain the present invention, and do not constitute a limitation to the present invention.

[0015] FIG. 1 is a schematic diagram of a fixing bracket and a lens barrel in an embodiment.

[0016] FIG. 2 is a schematic diagram of the structure of the lens barrel holder of the embodiment.

[0017] FIG. 3 is a schematic view of the structure of the lens barrel of the embodiment.

[0018] FIG. 4 is a schematic diagram of a partial structure of an embodiment.

[0019] In the figure: 1. Mounting end, 2. Lens tube bracket, 3. Lens tube, 4. M3 screw hole, 21. Fixing ring, 22. Ring, 23. Horizontal extension, 24. Longitudinal bracket , 31. Fixed sleeve, 32. Fixed base, 33. Lens, 34. Laser diode, 35. Piezoelectric ceramic, 36. Screw.

Detailed ways

[0020] 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, and cannot be interpreted as a technical solution to the present invention. limits.

[0021] In the figure, a laser strobe lighting device and method for an optical microscope, including a laser diode, a lens barrel, a lens, a fixed bracket, a drive circuit, and a power supply; the lens barrel consists of a fixed sleeve and a fixed base Composition, the fixed sleeve is mechanically connected with the fixed base; the laser diode is mechanically connected with the fixed base, the lens is mechanically connected with 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 fixing ring is mechanically connected to the mounting end; the application has a simple structure, low processing cost, and

Small size, easy to install and disassemble.

[0022] The fixing bracket is composed of a mounting end and a barrel bracket for fixing the laser diode. The mounting end is mechanically connected with the microscope objective lens or the microscope barrel. The outer surface is provided with 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 be matched with the external thread on an industrial microscope barrel. The mounting end in Figure 1 also has a horizontal M3 screw hole. The M3 screw alone can be used to fix the mounting end on the microscope barrel or objective lens, which is suitable for industrial microscope barrels without external threads. The thread on the outer surface of the lower end of the mounting end is M32, which is matched with the inner thread of the fixing ring. The mounting end is made of plastic material, which is simple to process and has low manufacturing cost. At the same time, the plastic material is softer than the metal material of the microscope and will not cause damage to the microscope. The lens barrel holder is composed of a fixed ring, a circular ring, a plurality of laterally extending ends and a longitudinal support. The fixed ring has an outer diameter of 39 mm and a height of 5 mm. The inner part of the fixed ring is provided with an M32 thread. The fixing ring is made of plastic material.

[0023] In FIG. 2, the fixed ring is mechanically connected to the circular ring, the circular ring is mechanically connected to the lateral extension end, and the lateral extension end is connected to the longitudinal direction. The brackets are mechanically connected; the included angles between adjacent laterally projecting ends are equal, and the longitudinal brackets are provided with a "one" shape at the bend of the outer end of the laterally projecting ends. The mounting hole of the lens barrel is mechanically connected to the mounting end through a fixing ring. The inner diameter of the ring of the lens barrel holder is 33 mm and the outer diameter is 39 mm. The ring and the fixing ring on the mounting end are bonded by glue. The length of the lateral extension end is 18.75 mm and the width is 3.5 mm. The longitudinal bracket is at the bend of the outer end of the laterally extending end, and the angle between the plane of the longitudinal bracket and the plane of the laterally extending end is 90 degrees. The length of the longitudinal bracket is 35 mm and the width is 7 mm. The longitudinal bracket is provided with a "one"-shaped mounting hole. 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. The distance between the hole and the side of the longitudinal support is 2 mm. The ring, the lateral extension end and the longitudinal bracket are an integrated structure, all made of 1 mm stainless steel steel plate. The processing technology of the 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 with the mounting end, and the lens barrel bracket is mechanically connected with the mounting end through the fixing ring.

[0024] In FIG. 3, the diameter of the lens barrel is 8 mm, the length is 10 mm, the length of the fixed sleeve of the lens barrel is 5 mm, and the screw thread is M3. The lens barrel is fixed on the lens barrel holder by the screw. . In Fig. 4, the lens barrel is screwed together with a nut through the mounting hole on the longitudinal bracket through a screw, and fixed on the longitudinal bracket. By screwing 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 irradiated on the sample under test at a certain angle. In Figure 1 and Figure 2, the barrel holder and the mounting end are connected by threads. The barrel holder has a centerline and can rotate around the centerline so that the laser diode illuminates the sample from different directions. For some samples, it is necessary to use a specific angle or a specific direction of light to illuminate in order to clearly show the subtle structure and achieve a good shooting effect. This application effectively solves the problem of adjusting the angle and direction of the incident light. In some cases, adjusting the angle and direction of the incident light can also reduce or even eliminate laser speckles in the field of view. The structure disclosed in this application helps eliminate speckles and improve the shooting effect.

[0025] The mounting end and the lens barrel holder are connected by a thread, and the height of the lens barrel holder can be adjusted without changing the position of the mounting end; it can also be easily adjusted when the angle of the lens barrel is fixed. The height of the converging position enables the beam to be accurately converged on the surface of the sample to be tested.

[0026] In the embodiment, a piezoelectric ceramic sheet is installed at the tail of the lens barrel. By applying an AC voltage to the piezoelectric ceramic sheet, the vibration of the piezoelectric ceramic causes the laser diode to vibrate, which reduces the contrast of the speckle pattern and can Reduce the influence of laser speckle on the quality of pictures taken by the microscope.

[0027] The driving circuit supplies power to multiple laser diodes at the same time, and the multiple laser diodes simultaneously illuminate the sample under observation from different directions. The drive circuit can receive an external pulse voltage signal as a trigger signal. When there is no trigger signal, the output current of the drive circuit is less than the threshold current of the laser diode, and the laser diode does not produce laser; when there is a trigger signal

When the current output by the drive circuit is greater than the threshold current of the laser diode, the laser diode generates laser light. Because there are multiple lens barrels and laser diodes on the lens barrel holder, multiple laser diodes are used for simultaneous illumination, which increases the uniformity of illumination and improves the brightness of illumination. The light spots generated by each laser diode are superimposed on each other, reducing laser speckle. The laser light emitted by each laser diode is not coherent with each other. After being superimposed, the overall coherence is reduced, and the intensity of the speckle will be significantly reduced.

[0028] In the embodiment, when the laser diode is stimulated to emit, the working current is continuously changed, and the continuous change of the working current will cause the wavelength of the emitted laser to continuously change, thereby reducing the coherence of the light and improving the imaging quality; the continuous change of the working current will This leads to continuous changes in the temperature of the PN junction and/or continuous changes in the resonant cavity, which further reduces the coherence of light. In one embodiment, the working current of the laser diode is a triangular wave. In another embodiment, the capacitor discharges the laser diode. At the beginning of each pulse, the current is the largest, and then the current decreases continuously; in the third embodiment, each pulse The capacitor is charged by the laser diode.

[0029] The laser diode in the embodiment is a blue laser diode with a wavelength of 450 nm. The laser tube has a small size, a long life, and a small divergence angle. The light output power is 80 milliwatts under 5V working voltage, and multiple laser diodes emit light at the same time and go out at the same time. The time 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, but there is no light, the CCD will not continue to be exposed to light, which meets the requirements for shooting fast-changing objects; The directivity is good, the light is concentrated on the sample area on the stage, the waste of light is less, the energy saving is achieved, and the mirror is not required, the production cost is reduced, the maintenance is more convenient, and the maintenance cost is low; due to the high laser brightness and It is easy to adjust the laser intensity, each light pulse has enough photons falling on the CCD, and the captured image is clear and the signal-to-noise ratio is good; because the wavelength of the laser is 450nm, there is no light of other wavelengths, compared with white light illumination , The resolution of the microscope is also improved; because the color filter is not used, the light utilization rate of the system is improved, and the overall light utilization rate of the laser diode is also improved, and the average power of the laser diode is lower due to the use of pulsed illumination. There is no need to use a heat sink, which simplifies the mechanical structure and the circuit structure, reduces the cost, and reduces the failure rate.

[0030] The present invention and the accompanying drawings show the preferred embodiments of the present invention. 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, for those skilled in the art, they can still comment on the foregoing. The technical solutions described in the embodiments are modified, or some of the technical features are equivalently replaced. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.