WO1997001115A1 - Fresnel lens - Google Patents
Fresnel lens Download PDFInfo
- Publication number
- WO1997001115A1 WO1997001115A1 PCT/NL1996/000238 NL9600238W WO9701115A1 WO 1997001115 A1 WO1997001115 A1 WO 1997001115A1 NL 9600238 W NL9600238 W NL 9600238W WO 9701115 A1 WO9701115 A1 WO 9701115A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- fresnel lens
- layer
- light
- lens according
- grooved
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/0018—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 with means for preventing ghost images
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B3/00—Simple or compound lenses
- G02B3/02—Simple or compound lenses with non-spherical faces
- G02B3/08—Simple or compound lenses with non-spherical faces with discontinuous faces, e.g. Fresnel lens
Definitions
- the invention concerns a Fresnel lens.
- the invention concerns a Fresnel lens which is adapted to alter the spatial distribution and to reduce the magnitude of scattered light generated in such a Fresnel lens.
- Fresnel lens In these such scattered light appears as a brilliant background, not only in the projected image, but also in the eyes of the person who uses the projector. That can interfere with the per- formance of the speaker.
- Fresnel lenses Fresnel prisms and other various predominantly flat surfaces used in micro- optical computer linkups. These include the surfaces employed to match optical fibers to lightsources and signal receptors. On all these surf ces undesirable scattered light of the type here discussed does in general appear.
- the aim of the invention is to provide a Fresnel lens wherein the intensity of the undesirable scattered light is decreased and the spatial distribution of the scattered is amended, so that the detrimental effects of such scattered light are reduced.
- figure 1 a cross section of a prior art Fresnel lens, to explain the disadvantages thereof;
- figure 2a a more detailed cross section of a part of the Fresnel lens depicted in figure 1;
- figure 2b a more detailed cross section of another part of the Fresnel lens depicted in figure 1;
- figure 3a a detailed view of a part of a Fresnel lens processed according to the invention;
- figure 3b a detailed view of another part of a Fresnel lens processed according to the invention;
- figure 4a a detailed view of a part of a Fresnel lens processed according another embodiment of the in ⁇ vention,- figure 4b: a detailed view of another part of a Fresnel lens processed according said other embodiment of the invention.
- Figure 1 shows a prior art Fresnel lens 1, its axis 2, and its focal point 3, lightbeams 4 incident on Fresnel lens 1, and parallel to its axis 2, lightbeams 5 concentrated near the focal point 3, and scattered light ⁇ beams 6.
- Figure 2a and figure 2b display enlarged sections of a prior art Fresnel lens 1, that is its flat surface 7 as well as on a grooved surface sections, the gently in ⁇ clined side surfaces 8, the steeply inclined side surfaces 9, concave edges 10 and convex edges 11. Also visible are the points of origin of some scattered light ⁇ beams 6.
- Figure 3 The main feature of our invention is illustrated by Figure 3.
- the production of undesirable scattered light is inhibited by covering the side surfaces 9, and edges 10 and 11 by a lightabsorbing layer 12, either completely (Figure 3a) or partially ( Figure 3b) .
- FIG. 4a or part of ( Figure 4b) the side surfaces 9, and edges 10 and 11 in a manner which causes them to diffusely reflect light, so that any sufficiently small element of a surface treated such, and that can be con-sidered so small, that it is a sufficiently good approximation of a flat surface, will scatter a lightbeam normally incident on it into a solid angle being essentially IT with an approximately uniform intensity distribution. If the intensity distribution of scattered light from an untreated Fresnel lens is not like this, then with such treatment one can achieve a more uniform di ⁇ tribution of the scattered light, that is, one can de ⁇ crease the scattered light intensity in those directions which receive more of the scattered intensity from the untreated lens.
- Figure 4a and 4b show the so treated surfaces 13.
- the lightabsorbing layer 12 indicated in Figure 3 can be realized, for example, by applying a paint cover to the appropriate sections of side surfaces 9 and edges
- the agent is rinsed off and finally the surface is dried.
- the chemical agent may be fluorine.
- the appropriate sur ⁇ faces are furbished or ground. If the surface in question is made of glass, then it can be ground using diamond powder, or by sandblowing. If the surface in question is made of a material softer than glass, then it can usually be ground using a powdered material softer than diamond. If the surface to be treated is readily deformed at room temperature, then it is advisable to perform the furbishing or grinding at low temperatures.
- a Fresnel lens By covering sections of the grooved surface of a Fresnel lens with a protective layer, one can achieve that said lightabsorbing layer covers only the non ⁇ protected areas of the surface, or that a diffusely scattering surface is only formed where said protective layer does not cover the surface.
- Such lightabsorbing layer can be useful, even if it strongly absorbs light only over part of the spectral region of the undesired scattered light.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Elements Other Than Lenses (AREA)
Abstract
The invention concerns a Fresnel lens comprising at least one grooved surface, whereby at least a portion (9, 10, 11) of said grooved surface is covered with a layer (12) avoiding scattering light of frequencies being within the frequency range of light prone to be scattered by the Fresnel lens. The production of undesirable scattered light is inhibited by covering the surfaces (9) and edges (10, 11) and by a lightabsorbing layer (12), either completely or partially.
Description
FRESNEL LENS
The invention concerns a Fresnel lens.
In particular the invention concerns a Fresnel lens which is adapted to alter the spatial distribution and to reduce the magnitude of scattered light generated in such a Fresnel lens.
Although most of the light incident on a Fresnel lens along the lens axis is generally concentrated by the lens near it's focal point, the remainder of the- light energy is scattered into points other than near the focal point as is clearly shown in figure 1.
The presence αf this scattered light is often un¬ desirable.
For example, when viewing the surroundings through a Fresnel lens fastened to the rear or side window or the rear view mirror of a car, this type of scattered light manifests itself as a background glare. That glare reduces the quality of the perceived picture and is especially disturbing during darkness.
Another example concerns overhead projectors utilizing a Fresnel lens; in these such scattered light appears as a brilliant background, not only in the projected image, but also in the eyes of the person who uses the projector. That can interfere with the per- formance of the speaker. Although farther from everiday experience, but representing a potentially very important group of applications, are the Fresnel lenses, Fresnel prisms and other various predominantly flat surfaces used in micro- optical computer linkups. These include the surfaces employed to match optical fibers to lightsources and signal receptors. On all these surf ces undesirable scattered light of the type here discussed does in general appear.
The aim of the invention is to provide a Fresnel lens wherein the intensity of the undesirable scattered light is decreased and the spatial distribution of the
scattered is amended, so that the detrimental effects of such scattered light are reduced.
This aim is reached in that at least a portion of said grooved surface is covered with a layer avoiding scattering light of frequencies being within the frequency range of light prone to be scattered by the Fresnel lens.
The production of undesirable scattered light is inhibited by covering the surfaces and edges and by a lightabsorbing layer, either completely (Figure 3a) or partially (Figure 3b) .
Subsequently, the invention will be elucidated with the help of the drawings, which show: figure 1: a cross section of a prior art Fresnel lens, to explain the disadvantages thereof; figure 2a: a more detailed cross section of a part of the Fresnel lens depicted in figure 1; figure 2b: a more detailed cross section of another part of the Fresnel lens depicted in figure 1; figure 3a: a detailed view of a part of a Fresnel lens processed according to the invention; figure 3b: a detailed view of another part of a Fresnel lens processed according to the invention; figure 4a: a detailed view of a part of a Fresnel lens processed according another embodiment of the in¬ vention,- figure 4b: a detailed view of another part of a Fresnel lens processed according said other embodiment of the invention. Figure 1 shows a prior art Fresnel lens 1, its axis 2, and its focal point 3, lightbeams 4 incident on Fresnel lens 1, and parallel to its axis 2, lightbeams 5 concentrated near the focal point 3, and scattered light¬ beams 6. Figure 2a and figure 2b display enlarged sections of a prior art Fresnel lens 1, that is its flat surface 7 as well as on a grooved surface sections, the gently in¬ clined side surfaces 8, the steeply inclined side
surfaces 9, concave edges 10 and convex edges 11. Also visible are the points of origin of some scattered light¬ beams 6.
One can imagine Fresnel lenses both of whose surfaces are grooved, however, for the sake of simplicity we do not show such lenses in figure 2.
It is clear from the figures that a large fraction of the undesirable scattered lightbeams 6 is generated on the side surfaces 9 and on the concave edges 10 and convex edges ll. Indeed, these surface components do not directly participate in useful image forming, or focussing, but play a role in the generation of unwanted scattered light.
The main feature of our invention is illustrated by Figure 3. The production of undesirable scattered light is inhibited by covering the side surfaces 9, and edges 10 and 11 by a lightabsorbing layer 12, either completely (Figure 3a) or partially (Figure 3b) .
The spatial distribution of scattered light can be altered (Figure 4) by appropriately treating all of
(Figure 4a) or part of (Figure 4b) the side surfaces 9, and edges 10 and 11 in a manner which causes them to diffusely reflect light, so that any sufficiently small element of a surface treated such, and that can be con-sidered so small, that it is a sufficiently good approximation of a flat surface, will scatter a lightbeam normally incident on it into a solid angle being essentially IT with an approximately uniform intensity distribution. If the intensity distribution of scattered light from an untreated Fresnel lens is not like this, then with such treatment one can achieve a more uniform diε¬ tribution of the scattered light, that is, one can de¬ crease the scattered light intensity in those directions which receive more of the scattered intensity from the untreated lens. Figure 4a and 4b show the so treated surfaces 13.
The lightabsorbing layer 12 indicated in Figure 3 can be realized, for example, by applying a paint cover to the appropriate sections of side surfaces 9 and edges
10 and 11. The treated surfaces shown in Figure 4 can be realized in several ways. According to one method the appropriate sections of side surfaces 9 and edges 10 and
11 are first chemically treated with an appropriate agent, then the agent is rinsed off and finally the surface is dried. If the surface to be treated is glass, the chemical agent may be fluorine.
According to another method, the appropriate sur¬ faces are furbished or ground. If the surface in question is made of glass, then it can be ground using diamond powder, or by sandblowing. If the surface in question is made of a material softer than glass, then it can usually be ground using a powdered material softer than diamond. If the surface to be treated is readily deformed at room temperature, then it is advisable to perform the furbishing or grinding at low temperatures.
By covering sections of the grooved surface of a Fresnel lens with a protective layer, one can achieve that said lightabsorbing layer covers only the non¬ protected areas of the surface, or that a diffusely scattering surface is only formed where said protective layer does not cover the surface. Such lightabsorbing layer can be useful, even if it strongly absorbs light only over part of the spectral region of the undesired scattered light. We have experimentally demonstrated the feasibility of our invention on commercially available non-rigid Fresnel lenses. In the course of these experiments the lenses were illuminated by monochromatic as well as white light. As a result of covering the appropriate surfaces, we achieved a position dependent decrease in scattered light intensity of at least 50 %, even when the side surfaces 9 and concave edges 10 were essentially left
uncovered and only convex edges 11 were covered by a lightabsorbing surface.
Having illustrated and described the principles of our invention with reference to preferred embodiments, it should be apparent to those persons skilled in the art that the invention may be modified in arrangement and detail without departing from the invention. We claim as our invention all such modifications as come within the true spirit and scope of the following claimε.
Claims
1. Fresnel lens, comprising at least one grooved εurface, characterized in that at least a portion of said grooved surface is covered with a layer avoiding scattering light of frequencies being within the frequency range of light prone to be scattered by the Fresnel lenε.
2. Fresnel lens according to claim 1, characterized in that the layer is adapted for absorbing light of frequencies being within the frequency range of light prone to be scattered by the Fresnel lens.
3. Fresnel lens according to claim 1, characterized in that the layer iε a diffuεe reflecting layer.
4. Fresnel lens according to claim 3, characterized in that the diffuse reflecting layer is a layer with such properties, that, if a lightbeam whoεe frequency lieε within the frequency range of light prone to be εcattered by εaid Freεnel lenε, the lightbeam is normally incident on a sufficiently small εurface of εaid diffuse reflecting layer, said layer reflects said lightbeam into a solid angle of the order of magnitude of it radials with an intensity distribution that is substantially uniform over εaid εolid angle, said surface being sufficiently small whenever said area can be adequately approximated by a flat area.
5. Fresnel lens according to one of the claims 1-4, characterized in that the portion compriseε at leaεt partε of thoεe parts of the grooved surface that extend substantially parallel to the axis of the Fresnel lenε.
6. Fresnel lens according to one of the claims 1-5, characterized in that the portion comprises at least parts of the convex edges of the grooved surface.
7. Fresnel lens according to one of the claims 1-6, characterized in that the portion compriseε at leaεt partε of the concave edges of the grooved surface.
8. Fresnel lens according to claim 5, characterized in that the portion compriseε adjacent parts of the adjacent edges of the grooved surface.
9. Method for preparing a Fresnel lens according to one of the preceding claimε, characterized in that at leaεt a portion of the grooved εurface of the Freεnel lenε is covered by a layer avoiding scattering light of frequencies being within the frequency range of light prone to be scattered by the Freεnel lens.
10. Method according to claim 9, characterized in that the portion of the grooved surface of the lenε iε covered with light abεorbing material.
11. Method according to claim 9, characterized in that the portion of the grooved εurface is covered with a diffuεe reflecting layer.
12. Method according to one of the claimε 9-11, characterized in that the areas to be covered are preprocessed before the layer is applied.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU60178/96A AU6017896A (en) | 1995-06-13 | 1996-06-13 | Fresnel lens |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
HUP9501804 | 1995-06-13 | ||
HU9501804A HU9501804D0 (en) | 1995-06-20 | 1995-06-20 | Method and device for reducing diffuse lighting and changing distribution of the diffuse lighting rising in fresnel lenses |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1997001115A1 true WO1997001115A1 (en) | 1997-01-09 |
Family
ID=10986959
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/NL1996/000238 WO1997001115A1 (en) | 1995-06-13 | 1996-06-13 | Fresnel lens |
Country Status (3)
Country | Link |
---|---|
AU (1) | AU6017896A (en) |
HU (1) | HU9501804D0 (en) |
WO (1) | WO1997001115A1 (en) |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2828564A1 (en) * | 2001-08-08 | 2003-02-14 | Olivier Bataillard | Elimination of concentric myopic iridescence in optical lenses, by coating lens edges with acrylic paint after grinding |
EP2287641A1 (en) * | 2009-08-21 | 2011-02-23 | Mass Technology (H.K.) Ltd. | Fresnel lens sheet and luminaire using the same |
CN102230980A (en) * | 2011-06-24 | 2011-11-02 | 佘晓峰 | Method for manufacturing high-luminous-efficacy focusing solar Fresnel lens |
CN102590902A (en) * | 2012-02-28 | 2012-07-18 | 四川钟顺太阳能开发有限公司 | Fresnel condenser lens and design method of Fresnel condenser lens |
EP2490049A1 (en) * | 2011-02-21 | 2012-08-22 | Canon Kabushiki Kaisha | Diffractive optical element and manufacturing method for the same |
WO2014084411A1 (en) * | 2012-11-30 | 2014-06-05 | Essilor International | Fresnel lens and optical device |
JP2016176981A (en) * | 2015-03-18 | 2016-10-06 | 株式会社東芝 | Fresnel lens and manufacturing method thereof |
JP2017037325A (en) * | 2016-10-04 | 2017-02-16 | 日東光学株式会社 | Fresnel lens and illumination apparatus |
WO2022141134A1 (en) * | 2020-12-30 | 2022-07-07 | 深圳纳德光学有限公司 | Optical eyepiece system and head-mounted display device |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2534483A1 (en) * | 1974-08-02 | 1976-02-12 | Ichiro Hosaka | Fresnel lens esp. for overhead projectors - with dazzle reducing alternating optical and non-optical surfaces |
DE4022123A1 (en) * | 1990-07-11 | 1992-01-16 | Peter Nawrath | Prodn. of optically limiting plates - by giving acrylic] sheet suitable surface texture, coating it with light-sensitive material and illuminating it so that parts are blackened |
-
1995
- 1995-06-20 HU HU9501804A patent/HU9501804D0/en unknown
-
1996
- 1996-06-13 AU AU60178/96A patent/AU6017896A/en not_active Abandoned
- 1996-06-13 WO PCT/NL1996/000238 patent/WO1997001115A1/en active Application Filing
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2534483A1 (en) * | 1974-08-02 | 1976-02-12 | Ichiro Hosaka | Fresnel lens esp. for overhead projectors - with dazzle reducing alternating optical and non-optical surfaces |
DE4022123A1 (en) * | 1990-07-11 | 1992-01-16 | Peter Nawrath | Prodn. of optically limiting plates - by giving acrylic] sheet suitable surface texture, coating it with light-sensitive material and illuminating it so that parts are blackened |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2828564A1 (en) * | 2001-08-08 | 2003-02-14 | Olivier Bataillard | Elimination of concentric myopic iridescence in optical lenses, by coating lens edges with acrylic paint after grinding |
EP2287641A1 (en) * | 2009-08-21 | 2011-02-23 | Mass Technology (H.K.) Ltd. | Fresnel lens sheet and luminaire using the same |
CN101994986A (en) * | 2009-08-21 | 2011-03-30 | 马士科技有限公司 | Fresnel lens sheet and luminaire using the same |
US9612372B2 (en) | 2011-02-21 | 2017-04-04 | Canon Kabushiki Kaisha | Diffractive optical element and manufacturing method for the same |
EP2490049A1 (en) * | 2011-02-21 | 2012-08-22 | Canon Kabushiki Kaisha | Diffractive optical element and manufacturing method for the same |
US9366791B2 (en) | 2011-02-21 | 2016-06-14 | Canon Kabushiki Kaisha | Diffractive optical element and manufacturing method for the same |
CN102230980A (en) * | 2011-06-24 | 2011-11-02 | 佘晓峰 | Method for manufacturing high-luminous-efficacy focusing solar Fresnel lens |
CN102590902A (en) * | 2012-02-28 | 2012-07-18 | 四川钟顺太阳能开发有限公司 | Fresnel condenser lens and design method of Fresnel condenser lens |
WO2014084411A1 (en) * | 2012-11-30 | 2014-06-05 | Essilor International | Fresnel lens and optical device |
US9709820B2 (en) | 2012-11-30 | 2017-07-18 | Essilor International (Compagnie Generale D'optique) | Fresnel lens and optical device |
JP2016176981A (en) * | 2015-03-18 | 2016-10-06 | 株式会社東芝 | Fresnel lens and manufacturing method thereof |
JP2017037325A (en) * | 2016-10-04 | 2017-02-16 | 日東光学株式会社 | Fresnel lens and illumination apparatus |
WO2022141134A1 (en) * | 2020-12-30 | 2022-07-07 | 深圳纳德光学有限公司 | Optical eyepiece system and head-mounted display device |
Also Published As
Publication number | Publication date |
---|---|
HU9501804D0 (en) | 1995-08-28 |
AU6017896A (en) | 1997-01-22 |
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