FR2282656A1 - IMPROVED LOW-GLARE OVERHEAD - Google Patents

IMPROVED LOW-GLARE OVERHEAD

Info

Publication number
FR2282656A1
FR2282656A1 FR7525722A FR7525722A FR2282656A1 FR 2282656 A1 FR2282656 A1 FR 2282656A1 FR 7525722 A FR7525722 A FR 7525722A FR 7525722 A FR7525722 A FR 7525722A FR 2282656 A1 FR2282656 A1 FR 2282656A1
Authority
FR
France
Prior art keywords
glare
overhead
improved low
improved
low
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
FR7525722A
Other languages
French (fr)
Other versions
FR2282656B1 (en
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
3M Co
Original Assignee
Minnesota Mining and Manufacturing Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US05/554,417 external-priority patent/US3982822A/en
Application filed by Minnesota Mining and Manufacturing Co filed Critical Minnesota Mining and Manufacturing Co
Publication of FR2282656A1 publication Critical patent/FR2282656A1/en
Application granted granted Critical
Publication of FR2282656B1 publication Critical patent/FR2282656B1/fr
Granted legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form
    • B32B3/26—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer
    • B32B3/30—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer characterised by a layer formed with recesses or projections, e.g. hollows, grooves, protuberances, ribs
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
    • G02B19/0004—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed
    • G02B19/0009—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed having refractive surfaces only
    • G02B19/0014—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed having refractive surfaces only at least one surface having optical power
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
    • G02B19/0033—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use
    • G02B19/0047—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source
    • 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
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/132—Overhead projectors, i.e. capable of projecting hand-writing or drawing during action
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/40—Properties of the layers or laminate having particular optical properties
    • B32B2307/418—Refractive
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2551/00—Optical elements

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Overhead Projectors And Projection Screens (AREA)
  • Projection Apparatus (AREA)
  • Lenses (AREA)
  • Liquid Crystal (AREA)
FR7525722A 1974-08-21 1975-08-20 IMPROVED LOW-GLARE OVERHEAD Granted FR2282656A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US49913874A 1974-08-21 1974-08-21
US05/554,417 US3982822A (en) 1975-03-03 1975-03-03 Composite Fresnel lens assembly

Publications (2)

Publication Number Publication Date
FR2282656A1 true FR2282656A1 (en) 1976-03-19
FR2282656B1 FR2282656B1 (en) 1978-04-07

Family

ID=27053045

Family Applications (1)

Application Number Title Priority Date Filing Date
FR7525722A Granted FR2282656A1 (en) 1974-08-21 1975-08-20 IMPROVED LOW-GLARE OVERHEAD

Country Status (9)

Country Link
JP (1) JPS5343825B2 (en)
AU (1) AU475642B2 (en)
BR (1) BR7505320A (en)
DE (1) DE2537547C3 (en)
FI (1) FI63118C (en)
FR (1) FR2282656A1 (en)
GB (1) GB1520471A (en)
IT (1) IT1041287B (en)
SE (1) SE418423B (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2472197A1 (en) * 1979-12-18 1981-06-26 Cintra Daniel Fresnel lens for TV screen - has grooves with sidewall being functions of groove and lens radii
DE4207940C2 (en) * 1992-03-12 1995-08-17 Gerd Kueppersbusch Labeling device
US5296882A (en) * 1992-12-21 1994-03-22 Minnesota Mining And Manufacturing Company Overhead projector with catadioptric fresnel lens
JP2957910B2 (en) * 1994-07-08 1999-10-06 大日本スクリーン製造株式会社 Lighting equipment

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2224783A1 (en) * 1973-04-09 1974-10-31 Leitz Ernst Gmbh

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3511563A (en) * 1967-11-14 1970-05-12 Minnesota Mining & Mfg Projector

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2224783A1 (en) * 1973-04-09 1974-10-31 Leitz Ernst Gmbh

Also Published As

Publication number Publication date
DE2537547A1 (en) 1976-03-11
FI752349A (en) 1976-02-22
BR7505320A (en) 1976-08-03
DE2537547B2 (en) 1980-10-02
SE418423B (en) 1981-05-25
JPS5343825B2 (en) 1978-11-22
JPS5152827A (en) 1976-05-10
IT1041287B (en) 1980-01-10
GB1520471A (en) 1978-08-09
AU475642B2 (en) 1976-08-26
FI63118B (en) 1982-12-31
DE2537547C3 (en) 1981-05-27
AU8411775A (en) 1976-08-26
FR2282656B1 (en) 1978-04-07
SE7508976L (en) 1976-02-23
FI63118C (en) 1983-04-11

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Legal Events

Date Code Title Description
ST Notification of lapse