CN1116453A

CN1116453A - Diffraction viewing device

Info

Publication number: CN1116453A
Application number: CN 94190877
Authority: CN
Inventors: 格雷厄姆·迪尤尔; 格雷姆·布洛克; 达夫妮·弗林; 史蒂文·马蒂纳佐; 贝林达·斯特宁; 彼得·塞缪尔·阿瑟顿
Original assignee: Mikoh Technology Ltd
Current assignee: Mikoh Technology Ltd
Priority date: 1993-11-05
Filing date: 1994-11-01
Publication date: 1996-02-07

Abstract

A viewing device to aid in authenticating an optical surface (100). The device includes a laser diode (101) which produces a beam of light (103). The device includes a viewing screen (107) which receives a diffracted image produced by the beam (103) illuminating the surface (100). The device further includes a lens system (102) which causes the diffracted beam to be focused on the viewing screen (107).

Description

Diffraction viewing device

The present invention relates to a kind of help and distinguish the true and false, thereby help the discrimination in this object source and the device of identification attached to the Difraction surface on the object.

The present invention relates to optics discrimination and recognition technology, more particularly but be not uniquely, relate to of the application of this technology credit card, I.D., banknote, check and various types of products.More particularly, the device that the present invention relates to help the true and false of Difraction surface to distinguish and discern.

Diffraction image can be used for the true and false of a Difraction surface of visual means (and electronic method) affirmation.A shortcoming utilizing the collimated laser light bundle to produce this diffraction image is, this light beam may not can produce distinctness, diffraction image clearly, thereby difference real optical diffraction surface may not can be provided and utilize the ability on the forgery surface of holographic recasting (being sometimes referred to as holographic copy) fabrication techniques.

The objective of the invention is to overcome or from improving above-mentioned shortcoming in essence.

Here disclose a kind of help and distinguish the device of the true and false of an optical surface, this surface can produce a projected image with an incident beam, and said apparatus comprises:

A substrate;

One is installed in this suprabasil LASER Light Source, is used to provide a light beam, and makes this light beam along predetermined path projection, and the above-mentioned LASER Light Source above-mentioned optical surface that is used for throwing light on is to produce a diffracted beam;

One is installed in above-mentioned suprabasil imaging surface, is used for receiving the above-mentioned diffracted beam from above-mentioned optical surface, makes to receive image projected on above-mentioned imaging surface; And

An optical lens system of placing along above-mentioned path, its layout makes, when placing a catoptron with the above-mentioned imaging surface of above-mentioned beam direction the time on the preferred positions of above-mentioned path at above-mentioned optical surface, above-mentioned optical lens system can focus on above-mentioned light beam on the above-mentioned imaging surface.

This imaging surface preferably be made up of an image receiving element that can see through light, makes it possible to from any unilateral observation of said elements above-mentioned image on it.

By nonrestrictive example the preferred embodiments of the present invention are described referring now to accompanying drawing, in the accompanying drawings,

Fig. 1 is the synoptic diagram of a finder;

Fig. 2 is the synoptic diagram of the hot spot that produces on an optical surface of a preferred embodiment by Fig. 1 finder;

Fig. 3 is the synoptic diagram that adopts a hand-held finder of the employed observational technique of Fig. 1 device;

Should be noted that laser diode shown in Fig. 1 and 3 and lens combination are the parts of device inside, they are in order can clearly to illustrate shown in the figure.

In Fig. 1, schematically having drawn one is used for the device on viewing optics surface 100, and wherein Fig. 1 (a) is a side view, and Fig. 1 (b) is vertical view.The design of this optical surface 100 makes, will produce projected image by the optical diffraction process under correct illumination.

The output of laser diode 101 has produced light beam 103 through after the lens combination 102.Light beam 103 mirror 104 that is reflected reflexes on the optical surface 100.The effect of catoptron 104 is to be convenient to the arrangement of laser instrument 101 and lens combination 102 and to add shell on the one hand, also makes light beam 103 that best incident direction is arranged on optical surface 100 on the other hand: to be the direction that departs from vertical incidence a little in this situation.

Optical surface 100 makes the direct reflection of incident beam 103 partly become light beam 105, makes the diffraction of incident beam 103 partly become diffracted beam 106.The position of catoptron 104 makes light beam 103 be not orthogonal to optical surface 100.Make thus and separated an angle between incident beam 103 and the specular reflectance beam 105.

Light beam 105 and 106 is by 107 interceptions of a film viewing screen.Folded light beam 105 produces a hot spot 108 on film viewing screen 107, and diffracted beam 106 produces one or more images 109 (depending on the design of optical surface 100) on film viewing screen 107.A single image 109 has drawn among Fig. 1.Hot spot 108 and image 109 can both be from film viewing screen tops, for example 110 see from the position.The optimal viewing position of image 109 is that the observer is positioned at 110 places, position and watches along approaching the direction that diffracted beam 106 returns, as shown in Figure 1.It is noted that optical surface 100 may produce the diffracted beam beyond the light beam 106, will produce senior inferior diffraction image with the conjugate image of image 109 conjugation thereby produce the optical surface 100 under typical situation of diffraction image beyond the image 109-for example.But under layout shown in Figure 1, have only image 109 just observed screen 107 interceptions.Because optical surface 100 picture that produced normally conjugation occurs in couples, make it to receive to be positioned at optical surface 100 tops and image that be parallel to this surperficial half-plane so generally shield 107 placement.The design of film viewing screen 107 preferably makes its energy scattering diffracted beam 106, thereby can see image 109 in a range of view angles of the either side in film viewing screen 107 both sides.

Finder shown in Figure 1 can be a hand-held, thereby it may not be positioned on the position facing to optical surface 100.The relative orientation between finder and the optical surface 100 is depended in the location of film viewing screen 107 epigraphs 109.Contain an alignment point 111 on the film viewing screen 107,, when hot spot 108 drops on the alignment point 111, just reached correct aligning to help the aligning of finder with respect to optical surface 100.

Diffraction image 109 is important for obtaining clearly on film viewing screen 107 in the correct focusing of light beam 103.The layout of lens combination 102 should can make preferably that light beam 103 focuses on the film viewing screen 107 well when replacing optical surface 100 with a level crossing.Should see that finder shown in Figure 1 may be the part of handheld apparatus, so the distance between this device and the optical surface 100 may change.Should determine seeing the scope of the operating distance between device and the optical surface in this case, and the layout of lens combination 102 should make that when replacing optical surface 100 with a plane mirror, light beam 103 just in time focuses on the film viewing screen 107 under the maximum functional distance.For example, when greater than this maximum functional apart from the time, that image 109 will become will be big and more unintelligible (also promptly, the ratio of soft edge scope and picture size increases), thereby will present significantly and degrade.And for example, when less than this maximum functional apart from the time, image 109 will diminish and be more unintelligible, but size reduce the trend that will have the image definition covered to descend, make this image still acceptable concerning naked eyes.

Light beam 103 will produce a hot spot on optical surface 100.Fig. 2 is the synoptic diagram of hot spot 200 on optical surface 100 of seeing from optical surface 100 tops.Because the character of laser diode 101, unless used correcting optical element in lens combination 102, hot spot 200 generally presents elliptical shape.In certain embodiments, optical surface 100 may be made of the repeated arrangement pattern of some elementary cells 201, as shown in Figure 2.Wherein each unit 201 all contains an optical surface that can produce diffraction image 109.Unit 201 among Fig. 2 is foursquare, but should be realized that other cell configuration also is fine.In such an embodiment, preferably make the length of an elliptical shaft of oval hot spot 201 or two elliptical shafts approach the characteristic dimension of unit 201.Fig. 2 shows a typical example, and wherein oval hot spot 200 is aimed at unit 201, and oval minor axis length approaches the length of side of square shaped cells 201.It may be important that this condition is thrown light on this requirement fully for the unit that guarantees to have only when any single job no more than delegation or row.

In order to reach focusing requirement and the geometric properties of hot spot 200 on optical surface 100 simultaneously about light beam 103, may need or lens combination 102 is placed near laser instruments 101, perhaps use light hurdle confine optical beam 103, perhaps take this two measures simultaneously.

Fig. 1 finder that preferably can satisfy in conjunction with the illustrated optical condition of Fig. 2 can adopt in handheld apparatus, and Fig. 3 promptly is the vertical view that this device is shown.Laser instrument 101, lens combination 102, catoptron 104 and film viewing screen 107 all are placed in (comprising alignment point 111) head of hand-held finder 300.The battery that drive laser is used (and any relevant electronic circuit, comprise for example surge protection circuit) can be placed in the handgrip part 301 of device 300.A break-make pushbutton switch 302 that is positioned at handgrip 301 sides is controlled the power supply of laser instrument 101 and any relevant circuit.Just in time be positioned at when finder 300 on the tram of optical surface 100 tops, and during laser instrument 101 energized, on film viewing screen 107, will produce a flare 108 and one or more diffraction image 109.

Optical surface 100 may be a part that has the label of bar code (or the readable information of other machines) simultaneously.Therefore hand-held finder 300 preferably also contains the device that is used for reading bar code or other forms of machine sensible information.

For example, in a preferred embodiment, device 300 can comprise a bar code reader, and its bar code reading head 303 is placed in this device, makes device 300 not only to be used as finder but also to be used as bar code reader easily, and is for example shown in Figure 3.Both available buttons switch 302 operations of bar code read out function, the also available push-botton operation that another separates.Device 300 promptly can self have been stored bar code information for afterwards extraction, also can show bar code information, perhaps can also when reading, pass through certain contact (for example cable connection, infrared ray contact, radio-frequency association etc.) output bar code information.

Should see, might make some changes design shown in Figure 1.

For example, can be arranged in laser diode 101 and optical lens system 102 on the position of the output beam 103 that can produce direct directive optical surface 100, and not need to adopt catoptron 104.

Embodiment described herein has used plane film viewing screen 107.Yet should see, can replace it, so that the distortion of one or more diffraction image 109 minimizes with the curved surface film viewing screen.

Technology described herein both can be used for hand-held finder as shown in figure 3, also can be used for the desktop finder.Under desktop finder situation, said apparatus can contain for example line of rabbet joint or the such device of certain tolerant device, holding the object that has optical surface 100, and makes optical surface 100 on this object with respect to incident beam 103 location thus.For example, for optical surface 100 attached to the situation on the card, then the desktop finder can have a line of rabbet joint or " picture box " orientation angle, hold above-mentioned card, and help above-mentioned card location, make that the optical surface 100 on the above-mentioned card is correctly located with respect to above-mentioned incident beam 103.

Claims

1, the finder of the true and false of an other optical surface is debated in a kind of help, and this surface is suitable for producing a projected image with an incident beam, and said apparatus comprises:

A substrate;

2, according to the device of claim 1, wherein above-mentioned imaging surface is made up of an image receiving element that can see through light, makes it possible to observe on said elements above-mentioned image.

3, according to the device of claim 2, wherein above-mentioned image receiving element is frosted.

4, according to claim 1,2 or 3 device, wherein above-mentioned image receiving element has an alignment portion, and this part is used for by the above-mentioned beam lighting through above-mentioned mirror reflects, to help the aligning of this device.

5, according to the device of claim 1, it also comprises one along the reflecting surface of above-mentioned road through laying, make above-mentioned path form, and above-mentioned first tilt with respect to above-mentioned second portion by first from above-mentioned light source to above-mentioned reflecting surface and second portion from above-mentioned reflecting surface to above-mentioned precalculated position.

6, according to claim 5 device, wherein above-mentioned first is an acute angle with respect to the pitch angle of above-mentioned second portion.

7, according to claim 6 device, wherein above-mentioned imaging surface is made up of an image receiving element, and above-mentioned image receiving element is made by material that can printing opacity.

8, according to the device of claim 7, wherein above-mentioned image receiving element is frosted.

9, according to claim 3 or 8 devices, wherein said apparatus can be handed.

10,1,2 or 3 device as requested, wherein above-mentioned optical lens system can produce a hot spot on above-mentioned optical surface, and this hot spot has predetermined geometrical property (size, shape etc.).

11, according to the device of claim 10, the geometric properties of wherein above-mentioned characteristic and above-mentioned optical surface is relevant.

12, a kind of finder, the illustrated device of Fig. 1 to Fig. 3 is identical with reference to the accompanying drawings with front here in essence for it.