Image Detection System and Method For Production at Least One Image Detection System

• US 20090179142A1
• Filed: 01/23/2007
• Published: 07/16/2009
• Est. Priority Date: 01/23/2006
• Status: Active Grant

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: Braeuer, Andreas, Brueckner, Andreas, Duparre, Jacques, Dannberg, Peter
• Granted Patent: US 7,897,903 B2
• Time in Patent Office: Days
• US Class Current: 250/208.100
• CPC Class Codes: G02B 3/0031 Replication or moulding, e.g. hot embossing, UV-casting, injection moulding
• CPC Class Codes: G02B 3/0056 arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085
• CPC Class Codes: H01L 27/14603 Special geometry or disposition of pixel-elements, address-lines or gate-electrodes
• CPC Class Codes: H01L 27/14605 Structural or functional details relating to the position of the pixel elements, e.g. smaller pixel elements in the center of the imager compared to pixel elements at the periphery
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H04N 23/55 Optical parts specially adapted for electronic image sensors; Mounting thereof
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

According to the invention, the image detection system contains optical channels arranged one next to the other with a respectively assigned microlens with aperture and in each case at least one detector located in the image plane, wherein the detectors are arranged such that the directions of the optical axes, which form in each case the connecting lines between lens apices and centre of the detectors, represent a function of the position of the respective optical channel, wherein at least one aperture stop arrangement (4) is provided between the microlenses (1′) with aperture (2′) and the detectors (6′, 8), wherein the distance between centres of the aperture stops (4′) is located between the distance between apices of the microlenses (1′) and distance between centres of the detectors (6′, 8) such that, depending on the position of the channels, the aperture stops (4′) are arranged with different offsets to the microlenses (1′) and the detectors (6′, 8) and are in each case located on a straight line with them.

Claims

1. An image detection system of optical channels arranged next to one another, in each case with an assigned microlens with an aperture diaphragm and in each case at least one detector lying in the image plane, wherein the detectors are arranged in a manner such that the directions of the respective optical axes forming in each case the connection lines between the lens apexes and the centre of the detectors, represent a function of the position of the respective optical channel, characterised in that

at least one diaphragm arrangement (4) is provided between the microlenses (1′

) with aperture diaphragm (2′

), and the detectors (6′

, 8), wherein the centre-to-centre distance of the diaphragms (4′

) lies between the apex distance of the microlenses (1′

) and the centre-to-centre distance of the detectors (6′

, 8), in a manner such that depending on the position of the channels, the diaphragms (4′

) are arranged differently offset to the microlenses (1′

) and the detectors (6′

, 8), and in each case lie pairwise on a straight line with these.

2. An image detection system according to claim 1, characterised in that the detectors (6,′

8′

) assigned to the respective channels are at least partly arranged in a manner, such that they lie in the projection of the microlenses of in each case adjacent channels or ones lying laterally even further away.

3. An image detection system according to claim 1, characterised in that the detectors are designed directly as detector pixels (8) on a substrate (7), or as detector pixels with a pinhole diaphragm (6′

) set in front.

4. An image detection system according to claim 1, characterised in that each optical channel detects at least one certain solid angular segment as a corresponding image point, in a manner such that the entirety of the transmitted image points on the detector arrangement permits a reconstruction of the object.

5. An image detection system according to claim 1, characterised in that the microlenses have different shapes such as spherical, elliptical, aspheric and likewise.

6. An image detection system according to claim 1, characterised in that microprisms are integrated into the microlenses.

7. An image detection system according to claim 1, characterised in that the microlenses are arranged on a convexly or concavely shaped base surface, and the detectors (6′

, 8) on an arcuate substrate surface.

8. An image detection system according to claim 1, characterised in that the offset of the diaphragms for the ghost image suppression, with respect to the microlenses (1′

) or the detectors (6′

, 8), is adapted to the angles of incidence to be imaged with the respective optical channel.

9. An image detection system according to claim 1, characterised in that light sources are arranged between the optical channels or groups of optical channels, or around the optical channels.

10. An image detection system according to claim 1, characterised in that in the image plane of the microlenses (1′

), at least one detector (6′

, 8) is replaced by a light source which directs, bundles and/or distributes the light from the image plane via the microlens (1′

), onto the object to be observed.

11. An image detection system according to claim 9, characterised in that the light sources are designed as LEDs, OLEDs, VCSEL or as LASER diodes.

12. An image detection system according to claim 1, characterised in that the detectors are designed as CMOS-sensors or CCD-sensors or as a photodiode array consisting of polymer material.

13. An image detection system according to claim 1, characterised in that for colour recordings, the detectors are designed as an image sensor which receives different colours in a separate manner directly in three pixel layers lying above one another.

14. An image detection system according to claim 1, characterised in that the visual fields of adjacent optical channels partly mutually overlap.

15. An image detection system according to claim 14, characterised in that the viewing angle difference between adjacent optical channels which is given by the angular distance between the respective optical axes, is smaller than half the width of the visual field of one channel.

16. An image detection system according to claim 1, characterised in that several diaphragm arrangements (4) are arranged in different planes between microlenses and detectors.

17. An image detection system according to claim 16, characterised in that the diaphragm arrangements (4) have different centre-to-centre distances to one another, and/or with different distance layers, are distanced to one another, and to the detectors or microlenses.

18. An image detection system according to claim 1, characterised in that the optical channels and the microlenses (1′

) are designed for a magnification of about 1, wherein the object-side solid angle which is assigned to each channel as an image point, is set with regard to its size such that in the object distance of the imaging system, the lateral extension of the object which corresponds to this solid angle is just as large as the distance of the channels.

19. An image detection system according to claim 1, characterised in that a first aperture diaphragm array (2) assigned to the microlenses and a second diaphragm array (4), by way of coating, are deposited onto a transparent objective body (3) on the front side and the rear side, a microlens array is arranged on the first aperture diaphragm array (2), and a transparent distance layer (5) on the second diaphragm array, and a substrate (7) with an array of detector pixels (8) lies below the distance layer, wherein, as the case may be, a pinhole diaphragm array (6) is deposited on the distance layer (5) or the substrate with the detector pixels.

20. An image detection system according to claim 19, characterised in that the objective body (3) consists of glass, the lens array and the distance layer of a structured polymer, the diaphragm array (2, 4) of an absorbing polymer or metal, and the pinhole diaphragm array (6) of metal layer or polymer layer.

23. The use of an image detection system according to claim 14, with an evaluation device for the position detection of point-like objects whilst utilising the relation of the intensities of adjacent optical channels, which are detected by the detectors.

24. The use of an image detection system according to claim 14, with an evaluation device for the orientation detection and position detection of edges by evaluating intensity values or contrast values, detected by the detectors, and using the relation of the intensities of adjacent optical channels

21. A method for manufacturing at least one image detection system with a transparent objective body, on whose front side and rear side, a first and a second diaphragm array of thin absorbing polymer or a metal is deposited by way of coating and lithography, then a microlens array is manufactured on the front side by way of UV-replication, and a distance layer on a rear side, both of a polymer which may be structured by photo-lithography, and the distance layer is connected to the substrate provided with a detector pixel array.

22. A method according to claim 21, characterised in that for forming an optowafer, several first and second diaphragm arrays, several microlens arrays and several distance layers arranged at a distance to one another, are deposited onto a continuous objective body, and are connected to a detector wafer with a plurality of detector pixel arrays and bonding pads deposited between the detector pixel arrays on the wafer, in a manner such that the spaces remaining free between the distance layers lie above the bonding pads, and that the optowafers and detector wafers connected in such a manner are singularised with a saw by several differently deep cuts lying next to one another such that camera chips are manufactured, with which the bonding pads on the detector chips laterally project beyond the remaining arrangement.