CN212112515U - Bright field and dark field directional reflection light source assembly based on single light source - Google Patents
Bright field and dark field directional reflection light source assembly based on single light source Download PDFInfo
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- CN212112515U CN212112515U CN202021197388.6U CN202021197388U CN212112515U CN 212112515 U CN212112515 U CN 212112515U CN 202021197388 U CN202021197388 U CN 202021197388U CN 212112515 U CN212112515 U CN 212112515U
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Abstract
The utility model provides a bright field and dark field directional reflection light source assembly based on a single light source, which can simultaneously meet the directional reflection light distribution requirement of realizing the bright field and the dark field and improve the fingerprint imaging quality; it includes light source, casing, logical light quantity regulating part, the light source adopts single light source structure, the light source assemble in the casing, logical light quantity regulating part set up in the light-emitting end of light source, just logical light quantity regulating part with the coaxial axle center setting of light source is located the light source with between the logical light quantity regulating part the slot has been seted up on the casing, the slot is used for cartridge anti-dazzling screen, anti-dazzling screen can hide light source central authorities are luminous.
Description
Technical Field
The utility model relates to a court science technical field specifically is bright field and dark field directional reflection light source assembly based on single light source.
Background
Photographing is an important link in fingerprint and other trace evidence inspection work, if visible fingerprints and fingerprints processed by a physical or chemical method are found on site or on inspection materials, photographing and recording are carried out as soon as possible so as to prevent the fingerprints from fading or being accidentally damaged; light distribution photography is to select a white light source or a light source with other wavelengths, adjust and control the brightness distribution of reflected light of a material to be detected by changing the incident angle and the direction of illumination light to enhance the contrast between fingerprint lines and an object background pattern, and play a role in weakening or eliminating the interference of the object background pattern, wherein, the light distribution photography has various methods, the most common bright field photography is directed reflection photography, the most common dark field photography is dark field photography, while in different fields, the types and conditions of fingerprints and objects thereof are different, and different light distribution methods are required to be selected to effectively show the fingerprint lines and detail characteristics, but different light distribution devices have single use, for example, the common directional reflector in the fingerprint photography can only be used for directed reflection photography of bright fields; the dark field light distribution device can only take dark field photography.
However, for the directional reflection photography of the bright field, a surface light source is generally adopted for illumination, the surface of a smooth plane object to which a fingerprint is attached is equivalent to a mirror, and the reflected surface light source image appears as a light background of the bright field; the light emitted by the fingerprint on the object under the irradiation of the light source belongs to mixed reflected light of diffuse reflection superposition directional reflection, has scattering property, has relatively less light rays entering the photographic device, and is expressed as dark lines with lower brightness than light background, but because the light emitting area of the surface light source used by the traditional directional reflector can not be adjusted, the surface light source image is much larger than the fingerprint image, the light emitted by the part of the surface light source corresponding to the surface light source image outside the fingerprint area does not contribute to increasing the brightness of the surface light source image in the fingerprint area, but can irradiate the fingerprint and the background pattern on the lower layer of the object surface, the brightness of the fingerprint lines and the background pattern is increased, so that the contrast between the fingerprint lines and the light background is reduced, the imaging quality of the fingerprint is poorer, and the background pattern is difficult to weaken or eliminate; for the dark field photography of the fingerprint, a point light source is generally adopted for illumination, the incident angle is 10-30 degrees, at the moment, light emitted by the light source is reflected by a smooth plane object, the light entering the photographic device is few and is expressed as a dark background of a dark field, the light emitted by the fingerprint on the object under the illumination of the light source belongs to mixed reflected light of diffuse reflection superposition and directional reflection, the mixed reflected light has scattering property, the light entering the photographic device is relatively more and is expressed as light-colored lines with higher brightness than the dark background, specifically, when the incident angle is smaller, the fingerprint lines are displayed brighter, but the conditions that the brightness of the fingerprint lines on two sides is uneven, and the edge lines are easily interfered by the reflected bright spots of the light source often occur; when the incident angle is larger, the brightness of the fingerprint lines is reduced, so that the contrast between the fingerprint lines and a dark background is reduced, and the fingerprint imaging quality is poorer.
Disclosure of Invention
To the above problem, the utility model provides a bright field and dark field directional reflection light source assembly based on single light source, it can satisfy the directional reflection grading requirement of realizing bright field and dark field simultaneously, improves fingerprint imaging quality.
The technical scheme is as follows: bright field and dark field directional reflection light source assembly based on single light source, it includes the light source, characterized in that: it still includes casing, light flux volume regulating part, the light source adopts single light source structure, the light source assemble in the casing, light flux volume regulating part set up in the light-emitting end of light source, just light flux volume regulating part with the coaxial axle center setting of light source is located the light source with between the light flux volume regulating part the slot has been seted up on the casing, the interpolation of slot assembles anti-dazzling screen for hide light source central authorities are luminous.
Further, the light shielding sheet comprises a light shielding area positioned in the center and a display area positioned at the periphery of the light shielding area;
further, the light source is assembled in the inner cavity of the shell, and the light flux adjusting piece is arranged at the front opening end of the shell on the light emitting side of the light source;
furthermore, the light transmission quantity adjusting part adopts an adjustable diaphragm, and the maximum light transmission aperture of the adjustable diaphragm is not smaller than the size of the light source;
furthermore, a metal substrate is arranged in the shell and is arranged at the rear part of the inner cavity, LED lamp beads are uniformly distributed on the metal substrate, a cover plate is arranged at the opening end of the rear part of the shell, a circuit interface electrically connected with the LED lamp beads is arranged on the cover plate, and the circuit interface is connected with an external power supply and a controller;
further, the light source comprises a light homogenizing plate which is arranged at the front part of the inner cavity.
The utility model has the advantages that the light-emitting area of the light source can be controlled by the light-transmitting quantity adjusting piece, the area of the light-colored background outside the fingerprint area is reduced as much as possible, the illumination intensity of the fingerprint lines and the lower-layer background pattern on the object surface is reduced, and the fingerprint image quality displayed by the light field directional reflection is better; in addition, the light source adopts a single light source structure, the shell positioned between the light source and the light flux adjusting piece is provided with a slot, the slot is used for inserting the shading sheet, the shading sheet comprises a shading area positioned in the center and a display area positioned at the periphery of the shading area, so that the requirement of realizing the directional reflection light distribution of a bright field and a dark field can be met simultaneously only by inserting the shading sheet to expose or shade the central area of the single light source according to the condition, the directional reflector device realizes two purposes, and a fingerprint image shown by the directional reflection of the dark field is different from a fingerprint image shown by a traditional dark field light distribution method, the line illumination is more uniform, the imaging quality is higher, and the use value is better.
Drawings
FIG. 1 is a side sectional view of the present invention;
FIG. 2 is a front view of the present invention;
FIG. 3 is a schematic structural view of a light-shielding sheet;
FIG. 4 is a state diagram of FIG. 2 with a light shielding sheet inserted;
FIG. 5 is a schematic view of the light emission in the bright field mode of FIG. 2;
FIG. 6 is a schematic view of illumination in the dark field mode of FIG. 4;
fig. 7 is a schematic view of the fingerprint showing device of the present invention cooperating with the directional reflector.
In fig. 1 to 7: 1. a housing; 2. a light source; 3. a light flux amount adjusting member; 4. a metal substrate; 5. a light homogenizing plate; 6. an inner cavity; 7. LED lamp beads; 8. a circuit interface; 9. a handle; 10. a blade; 11. a slot; 12. a shading sheet; 13. a display area; 14. a light-shielding area; 15. a directional mirror cylinder; 16. a beam splitter; 17. a camera; 18. a shading cylinder; 19. fingerprint lines; 20. a smooth planar object; 21. a cover plate; 22. a light source inlet; 23. a directional mirror device.
Detailed Description
The technical solution and the advantages of the embodiments of the present invention will be described in detail with reference to the accompanying drawings. The described embodiments are only some, not all embodiments of the invention. Based on the embodiment of the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
As shown in fig. 1 to 7, the single light source based bright field and dark field directional reflection light source assembly comprises a light source 2, a housing 1, and a light flux adjusting member 3, wherein the light source 2 adopts a single light source structure, the light source 2 is assembled in the housing 1, the light flux adjusting member 3 is arranged at the light emitting end of the light source 2, the light flux adjusting member 3 is coaxial with the light source 2, a slot 11 is arranged on the shell 1 between the light source 2 and the light flux adjusting member 3, the slot 11 is used for inserting a light shielding sheet 12, the light shielding sheet 12 can shield the central light emitting area of the light source 2, specifically, the light shielding sheet 12 comprises a light shielding area 14 in the center and a display area 13 around the light shielding area 14, the light-shielding area 14 is made of opaque light-shielding material, the display area 13 is made of colorless transparent material, and the light-shielding area of the light-shielding area 14 is to ensure that all fingerprint lines 19 required to be displayed in the dark field directional reflection mode fall within the range of the dark background image of the light-shielding area 14.
The light source 2 is assembled in the inner cavity 6 of the shell 1, and the light flux adjusting piece 3 is arranged at the front opening end of the shell 1 at the light emitting side of the light source 2; the light flux adjusting part 3 adopts the existing equipment, namely an adjustable diaphragm, the maximum light flux aperture of the adjustable diaphragm is not smaller than the size of the light source 2, namely the maximum light flux aperture of the adjustable diaphragm is ensured not to block the light emitting of the light source 2, the aperture of the diaphragm is adjusted by shifting the handle 9 on the adjustable diaphragm to adjust the position of the blade 10 on the adjustable diaphragm, and then the light emitting area of the light source 2 is controlled.
The metal substrate 4 is assembled at the rear part of the inner cavity 6, the LED lamp beads 7 are uniformly distributed on the metal substrate 4, the opening end of the rear part of the shell 1 is provided with a cover plate 21, the cover plate 21 is provided with a circuit interface 8 electrically connected with the LED lamp beads 7, the circuit interface 8 is connected with an external power supply (not shown in the figure) and a control circuit or a controller (not shown in the figure) for controlling the brightness of the LED lamp beads 7, and the control circuit or the controller can adopt the existing equipment or the existing technology so as to enable the brightness of the LED lamp beads to be; the light source 2 comprises a light equalizing plate 5, the light equalizing plate 5 is arranged in the front of the inner cavity 6, a space is reserved between the metal substrate 4 and the light equalizing plate 5, so that the light equalizing plate 5 can uniformly emit light under the irradiation of the LED lamp beads 7, the light emitting area of the light equalizing plate 5 is equal to the sum of the areas of the transparent material and the shading material of the shading sheet 12, and the light emitting intensity of the light equalizing plate 5 can meet the light distribution requirements of directional reflection of a bright field and a dark field.
As shown in fig. 7, the directional reflector device 23 includes a directional reflector cylinder 15 and a beam splitter 16 installed in the directional reflector cylinder 15 at 45 °, a light source inlet 22 is opened on the directional reflector cylinder 15 corresponding to the side of the beam splitter 16, the light source inlet 22 is connected to the light source 2, i.e. the axial line of the beam splitter 16 and the light source 2 is 45 °, the upper end of the directional reflector cylinder 15 is connected to the camera 17, the lower end of the directional reflector cylinder 15 is connected to the light shielding cylinder 18, the light shielding cylinder 18 usually adopts a multi-section telescopic structure, a fingerprint object (a smooth planar object 20 and a fingerprint line 19 attached on the surface thereof) is placed under the light shielding cylinder 18, the bright field and dark field directional reflector light source assembly based on a single light source of the present invention is placed right opposite to the light source inlet 22 of the directional reflector device 23, the beam splitter 16 reflects the light emitted from the light source 2 and irradiates the fingerprint, the light emitted by the fingerprint object is transmitted through the spectroscope 16 and then imaged by the camera 17, the shading cylinder 18 can prevent the ambient light from interfering with the imaging effect of the fingerprint lines 19, and the shading cylinder 18 can be extended and retracted to change the distance from the camera 17 to the fingerprint object.
The utility model discloses an implementation specifically as follows:
as shown in fig. 5, the bright field directional reflection fingerprint appears when the light source 2 is in the light emitting state: the circuit interface 8 is connected with an external power supply and a controller, the handle 9 is shifted to adjust the adjustable diaphragm to the maximum clear aperture, the light shading sheet 12 is not inserted into the slot 11, the single light source is turned on, the brightness of the LED lamp bead 7 is adjusted to the maximum, the light emitted by the light-equalizing plate 5 is reflected by the spectroscope 16 in the directional reflector device 23 and vertically irradiates on the fingerprint object, the surface of the smooth plane object 20 is equivalent to a mirror, the incident light is reflected and then enters the camera 17 to form an image after passing through the spectroscope 16, and the image is expressed as a light-colored background image of the light-emitting light-equalizing plate 5; while the fingerprint lines 19 attached on the surface of the smooth plane object 20 and the lower background patterns (not shown in the figure) on the surface of the smooth plane object 20 have scattering property under the irradiation of the light equalizing plate 5, the light rays transmitted through the spectroscope 16 and entering the camera 17 for imaging are relatively less, the fingerprint lines 19 are shown as dark lines with lower brightness than the light background images, the background patterns are weakened, the fingerprint object or the directional reflector device 23 is moved to place the fingerprint line 19 area at the center of the visual field observed in the camera 17, the light-passing aperture of the adjustable diaphragm is gradually adjusted to be small by stirring the handle 9, so that the light-colored background image is reduced but the fingerprint lines 19 can be completely covered, thereby reducing the illumination intensity of the fingerprint lines 19 and the lower background patterns on the surface of the smooth planar object 20, and adjusting the appropriate brightness of the light source until the appearance effect of the fingerprint lines is optimal.
As shown in fig. 6, dark field directional reflection fingerprint appears in the light emitting state of the light source 2: the setting of each parameter is consistent with that of the bright field directional reflection fingerprint in the embodiment, a bright field directional reflection fingerprint image is firstly displayed, the handle 9 is further shifted to adjust the adjustable diaphragm to the maximum clear aperture, the light shading sheet 12 is inserted into the slot 11, after the light shading sheet 12 is inserted, the central area of the light homogenizing plate 5 is shaded by the light shading area 14, and under the reflection of the surface of the smooth plane object 20, a dark background image of the light shading area 14 is displayed in the camera 17; while the reflected light of the fingerprint lines 19 attached to the surface of the smooth planar object 20 under the irradiation of the unshielded part of the light equalizing plate 5 has scattering property, the light rays passing through the light equalizing plate 16 and entering the camera 17 for imaging are relatively more, the fingerprint lines 19 are light lines with higher brightness than the dark background image, the distance from the camera 17 to the fingerprint object can be changed by adjusting the height of the shading cylinder 18, so that the incident angle of the unshielded part of the light equalizing plate 5 irradiating the fingerprint object is changed, the emergence of the fingerprint edge lines of the fingerprint is not influenced by the shallow image formed by the unshielded part of the light equalizing plate 5, the brightness of the fingerprint lines is higher, the handle 9 is turned to adjust the light aperture of the adjustable diaphragm to adjust the brightness of the light source 2 until the emergence effect of the fingerprint lines is optimal, compared with the traditional dark field image, the dark field directional reflection image in the embodiment has no bright spot interference, uniform line illumination, and high fingerprint line, The contrast is better, in this embodiment, the annular surface light source of the light splitting mirror reflection light distribution is used to replace the point light source which is located beside the camera lens and directly irradiates light distribution in the traditional method, which is a brand new fingerprint dark field display mode in the fingerprint light distribution phase, and the directional reflector device 23 realizes the function of one machine for two purposes.
To sum up, after the directional reflector device is matched with the directional reflector device, as long as the central area of a single light source is exposed or shielded by inserting the shading sheet 12, the directional reflector device can show both bright field directional reflection images and dark field directional reflection images, so that the directional reflector device which originally has only a single function can realize the function of one machine for two purposes; the light emitting area of the light source 2 is controlled by adjusting the adjustable diaphragm, the area of the light color background outside the fingerprint area is reduced as much as possible, the illumination intensity of the fingerprint lines 19 and the background pattern on the lower layer of the object surface is reduced, the quality of the fingerprint image displayed by bright field directional reflection is better, and in addition, compared with the traditional dark field image, the fingerprint image displayed by dark field directional reflection has no bright spot interference, uniform line illumination and better contrast, and is a brand new dark field display fixed extraction mode in the pattern light distribution phase.
It is obvious to a person skilled in the art that the invention is not restricted to details of the above-described exemplary embodiments, but that it can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.
Claims (6)
1. Bright field and dark field directional reflection light source assembly based on single light source, it includes the light source, characterized in that: it still includes casing, light flux volume regulating part, the light source adopts single light source structure, the light source assemble in the casing, light flux volume regulating part set up in the light-emitting end of light source, just light flux volume regulating part with the coaxial axle center setting of light source is located the light source with between the light flux volume regulating part the slot has been seted up on the casing, the interpolation of slot assembles anti-dazzling screen for hide light source central authorities are luminous.
2. The single light source based bright field and dark field directional reflection light source assembly of claim 1, wherein: the light-shielding sheet includes a light-shielding region located at the center and a display region located at the periphery of the light-shielding region.
3. The single light source based bright field and dark field directional reflection light source assembly of claim 1, wherein: the light source is assembled in the inner cavity of the shell, and the light flux adjusting piece is arranged at the front opening end of the shell on the light outlet side of the light source.
4. The single light source based bright field and dark field directional reflection light source assembly of claim 3, wherein: the light transmission amount adjusting piece adopts an adjustable diaphragm, and the maximum light transmission aperture of the adjustable diaphragm is not smaller than the size of the light source.
5. The single light source based bright field and dark field directional reflection light source assembly of claim 3, wherein: the LED lamp is characterized in that a metal substrate is arranged in the shell and is arranged at the rear part of the inner cavity, LED lamp beads are uniformly distributed on the metal substrate, a cover plate is arranged at the opening end of the rear part of the shell, a circuit interface electrically connected with the LED lamp beads is arranged on the cover plate, and the circuit interface is connected with an external power supply and a controller.
6. The single light source based bright field and dark field directional reflection light source assembly of claim 5, wherein: the light source comprises a light equalizing plate which is arranged at the front part of the inner cavity.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021197388.6U CN212112515U (en) | 2020-06-24 | 2020-06-24 | Bright field and dark field directional reflection light source assembly based on single light source |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021197388.6U CN212112515U (en) | 2020-06-24 | 2020-06-24 | Bright field and dark field directional reflection light source assembly based on single light source |
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| Publication Number | Publication Date |
|---|---|
| CN212112515U true CN212112515U (en) | 2020-12-08 |
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|---|---|---|---|
| CN202021197388.6U Active CN212112515U (en) | 2020-06-24 | 2020-06-24 | Bright field and dark field directional reflection light source assembly based on single light source |
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| CN (1) | CN212112515U (en) |
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- 2020-06-24 CN CN202021197388.6U patent/CN212112515U/en active Active
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