CA1189369A - Image transmission line - Google Patents
Image transmission lineInfo
- Publication number
- CA1189369A CA1189369A CA000405399A CA405399A CA1189369A CA 1189369 A CA1189369 A CA 1189369A CA 000405399 A CA000405399 A CA 000405399A CA 405399 A CA405399 A CA 405399A CA 1189369 A CA1189369 A CA 1189369A
- Authority
- CA
- Canada
- Prior art keywords
- transmission line
- image transmission
- image
- end surface
- incident
- 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.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/04—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings formed by bundles of fibres
- G02B6/06—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings formed by bundles of fibres the relative position of the fibres being the same at both ends, e.g. for transporting images
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B23/00—Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices
- G02B23/24—Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes
- G02B23/26—Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes using light guides
Abstract
ABSTRACT OF THE DISCLOSURE
An image transmitting optical fiber device is improved in contrast by limiting the incident angle of light applied thereto and/or by placing an antireflection member in the light path at one or both of the ends of the device.
An image transmitting optical fiber device is improved in contrast by limiting the incident angle of light applied thereto and/or by placing an antireflection member in the light path at one or both of the ends of the device.
Description
~L~8~36~
~3ACKGROUND OF THE INVENq'ION
The presen~ invention relates ~o improvements in an image transmission line using optical fibers and is intended to permit transmission of high contrast images and so forth.
BRIEF D~SCRIPTION OF THE DR}~WINGS
The present invention will hereina~ter be explained i.n de-tail by reference to the accompanying drawings, in which:
Figs. 1 and lA are illustrative view of light transmission in a conventional image transmission line;
Fig. 2 is a longitudinal sectional view of one embodiment of the image transmission line of the i.nvention, Figs. 3(a) and 3~b) are a longitudinal sectional view and a perspective view, respectively, of an image-receiving side of another embodiment of the image trans-mission line of the invention;
Fig. 4 is a schematic view of a t~sting apparatus for evaluating the contrast;
~3ACKGROUND OF THE INVENq'ION
The presen~ invention relates ~o improvements in an image transmission line using optical fibers and is intended to permit transmission of high contrast images and so forth.
BRIEF D~SCRIPTION OF THE DR}~WINGS
The present invention will hereina~ter be explained i.n de-tail by reference to the accompanying drawings, in which:
Figs. 1 and lA are illustrative view of light transmission in a conventional image transmission line;
Fig. 2 is a longitudinal sectional view of one embodiment of the image transmission line of the i.nvention, Figs. 3(a) and 3~b) are a longitudinal sectional view and a perspective view, respectively, of an image-receiving side of another embodiment of the image trans-mission line of the invention;
Fig. 4 is a schematic view of a t~sting apparatus for evaluating the contrast;
2~ Fig. 5 is an illustrative view of an evaluation method;
Fig 6 is an enlarged longitudinal sectional view of the incident end portion of another embodiment of the image transmission line of the invention;
Fig. 7 is an enlarged longitudinal sectional view of the incident end portion of still another embodiment of the image transmission line of the invention;
Fig 6 is an enlarged longitudinal sectional view of the incident end portion of another embodiment of the image transmission line of the invention;
Fig. 7 is an enlarged longitudinal sectional view of the incident end portion of still another embodiment of the image transmission line of the invention;
3~j~
1 Fig. ~ is a graph.obtalned by standardizing experimental results; and Fig. 9 is a graph showing experimental results.
One image transmission :Line for use in the trans-mission of images or patterns comp.rises a number of optical fiber elements bundled together in the condition that they are lined up with each other, where the optical fiber elements are composed of a core portion having a high re-fractive index and a cladding portion surrounding the core portion and having a low refractive index, wherein, by the difference in refractive index between the core portion and the cladding portion, light incident into the core portion is subjected repeatedly to total reflection by the boundary between the core and cladding portions whereby the l$ light is transmitted through the core portion. The image thus transmitted is sent to the emission end where it is magnified by an image-receiving lens and converted into images suitable for direct reading, photographing with a 35 mm camera, and so forthO
At the emission end of the image transmission line 01, i.e., at the image-receiving side, as illustrated in Fig. 1, light A transmitted through the core portion 02 is subiected to Frenel reflection and scattering by the emission end surface 03, producing noise light B. Thus, information containing light is mixed with noise light B, leading to a reduction in the contrast of the transmitted image. This phenomenon may also occur at the incident end.
36~
1 In the case of light B incident into the core portion 1, as shown in Fig~ lA, if the incident angle of the ligh-t B
is larger than the aperture number which is determined b~
the s-tructure of an optical fiber element 13, i.e., the critical angle which is determined by the difference in refractive index between the core portion la and the clad-ding portion 22, light B passes through the cladding portion 22 and leaks Erom the line. Also, iE there is an irreg-ularity (a) e.g., an air bubble, an impurity or the like, between the optical fiber elements, or in the boundary between the core portion 1 and the cladding portion 22, part of the leaked light is irregularily reflected, becoming noise light C which mixes with the information light trans-mitted through the core portion 1, thereby further reducing the contrast of the transmitted image. Furthermore, an irregularity (b) between the cladding portion and a metallic sleeve 14 provided at the incident end surface of the image transmission line will further increase the reduction in contrast of the transmitted image.
SUMMARY OF T~E INVENTION
The object of the invention is to overcome the above-described problems and to provide an image trans-mission line which permits transmission of high contrast images, etc. The present invention, therefore, relates to an image transmission line comprlsing a number of optical fiber elements bundled together in a condition such that they are aligned with.one another, characterized in that . ~
3~i~3 ] at least one of the incidents end surface and -the emission end surface of the image transmission line is provided with contrast improving means.
DETAILED DESCRIPTION OF TEIE PREFERRED EMBODI~qE~TS
____ Fig. 2 i9 a longitudinal sectional view of an embodiment of the image ~ransmission line of the invention.
A number of optical fiber elements 1 are bundled together such that they are aligned with each other to form an image transmission line 2. The image transmission line 2 is provided with an image-receiving plug 3 and an image side (camera) plug 4 at either end thereof. The image-receiving plug 3 and the plug 4 are further provided with an image-receiving lens 5 and a camera lens 6, respectively, at the top end thereof. At a top end surface 3a of the image~receiving plug 3, which is an emission end surface, commercially available AR Coat 7 (anti-reflection) is coated as a reflection-preventing membrane. Also, a top end surface 4a of the camera plug 4, which is an incident end surface, is coated with AR Coat 7. Thus, the reflection of the light reaching the top end surface 3a of the image-receiving plug 3 at the emission end is pro-vented, and no contamination of information light with noise light will occur. Moreover, since the reflection-preventing membrane enables the inhibition of repeated reflection between the image-receiving plug 3 and the image-receiving lens S and between the plug 4 and the camera lens 6, information light 36~
will not mix with noise light and~ therefore~ the contrast of the transmission image can be increasecl~
Pigs. 3~a) and 3(~b~ aTe a longitudinal sectional view and a perspective view, respectively, of an image-receiving pLug portion oF another embodiment of the image -transmission line of the inverl-tion.
In this embodiment, the reflection-preventing membrane is not coated directly on the top end surface of either the image-receiving plug or the source plug, but it is first pro-vided on the outer surface of a glass plate 8 made of quartz, for example, by coa-ting AR Coat, and the glass plate 8 with the reflection-preventing me~brane provided -thereo-n is then adhered and fixed to the top end surface of the image-receiving plug or the source-side plug through a liquid ~matching oil) having a refractive index which is equal or nearly equal to the re-fractive index oE the core portion of the optical fiber element.
Ill this adhesion-fixation procedure, when a hole or holes 9 are bored in the image-receiving plug 3 in the longitudinal direction thereof as illustrated in Fig. 3~b) and an adhesive is injected into the hole 9, the glass plate can be firmly adhered and the adhesion strength can be increased. Also, a glass plate can be provided at the source plug side although the above explanation has been made with respect to an embod~men-t where the glass plate is provided at the image-receiving plug side Such provision of the reflection-preventing membrane 36~
on the glass plate 8 can produce th.e same results as in the above-described ~embodiment, in which the reflection-preventi.ng membrane is coated directly on the top end sur:face of -the image-receiving or source-side plug.
The contrast-improving e-ffect in the image transmission line of the invention will hereina-fter be described by re:ference to the following experiment.
In an experiment, as illustrated in Fig. 4, a diffuse light source having a uniform surface brightness and having a diameter~ D ~= 2R) , of 65 mm was employed, and, at a distance Q ~lll mm) from the diffuse light source, an image fiber 11 (aperture number, NA: 0.28) was placed. The aperture number of the incident light, NAin, was set to 0.28, so as to agree with that of the image fiber ll. A glass plate with AR Coat coa-ted thereon was adhered and fixed to the image fi.ber 11 at the image-receiving side thereof in the same manner as shown in Fig. 3.
In this condition, a knife edge 12 was placed at the incident end sur-face of the image fiber 11, and the image of the knife edge 12 was scanned in a direction x, perpendicular to the knife edge 12 at the image-receiving side, which was the emission end surface and the received light level E was measuTed. The value of the light level E was standardized to obtain a curve as shown in Fig. 5. This curve can be approximately represented by equa-tion ~l) as described hereinafter, and the contras-t can be evalu-ated by the ~radient o~ the approximate straight line at the :' ' ' 3~
rising zone (see Text No. 1086 of the Japanese Electronic Communication Association ~eeting '81). Thusl the value of 1/~ (Fig. 5) was determined and the contrast was evaluated using the value 1/~.
x < 0 1/2 e~
X < 1 - 1/2 e~~XX (1) 'I'he value 1/~ of the ~resent image transmission line to which the glass plate with AR Coat provided thereon was fitted was 0.15 mm, whereas, on the other hand, in the con-ventional image transmission line with no such glass plate pro-vided thereto, the value of 1/~ was 0.26 mm. Thus, the improve-ment ratio, P, represented by the e~uation ~2) as described below, was 42%. This demonstrates that the contrast improving effect is considerably large.
p = (1/~ before improvement) ~ a'fter improvement) ~ before improvement) ~2) Fig. 6 is a longitudinal sectional view of an incident end portion of another embodiment of the image transmission line of the invention.
Between a camera lens 35 and the end of an optical fiber element 13 at the incident end portion of an image transmission line I is provided a hood 36 as a member for controlling the maximum incident angle of the incident light to not more than the critical angle. The hood 36 ~s secured to a metallic sleeve ,C~36~
14. In the hood 36 i5 bored a tapered hole which is divergent toward the top end thereof. The taper determines the maximum incident angle of the incident light~ Of the light rays inci-dent into the image transmission line I through -the camera lens 35, those ra.ys having an incident angle greater than the numerical apertuIeof the image transmission line I are prevented from enter-ing the image transmission line I by the hood 36, and only those rays having an incident angle less than the numerical aperture, i.e., les.s than a critical angle, are allowed to enter the image ~rans-mission line. Thus, all incident light is transmitted throughthe image transmission line I by repeated total reflection and, without contamination with noise light, infornati:on light can be transmitted; that is, high contrast images or the like can be transmitted to the emission end portion of the image transmission line I.
Fig. 7 is a longitudinal sectional view of the incident end portion of another embodiment of the image transmission line of the invention.
In an image transmission line I of this embodiment, the metallic sleeve 14 is not provided with a hood, but instead, a stopping ring 37 is provided as a stopping member in the camera lens 35. According to -the size of central hole diameter of the stopping ring 37, light rays incident upon the image transmission line I are limited to those rays having an incident angle less than the aperture number ~critical angle)~ permitting trans - 8 - ..
3~
mission of high contrast images or the like.
~ lereinafter, the effect obtained by con-trolling the incident angle to less -than the critical angle of the image transmission line at the incident end surface thereof will be exaplained by reference -to the following expe-riment.
In this e~periment, also illustrated by Fig. 4, by changing the diame-ter R of a diffuse light source 10 having uniform surface brightness, and without the provisîon of a hood 36 or a stopping ring 37 as described heTeinabove, the incident angle 20 to an image fiber ~numerical aperture NA = 0~28) was changed. The fiber was placed at a distance of lll mm from the light source 10. In this case, the relation between the dia-meter R, the incident angle 23, and -thenumerical aperture o-f the incident light NAin (= sin ~) was as shown in 'Iable 1. By placing a knife edge 12 at the incident end surface of the image fiber 11, the image of the knife edge 12 was scanned in a direc`
tion x perpendicular to the knife edge, and the received light level E was measured. The values of the light levels were standardized to obtain a curve as shown in Fig. 8.
The curve can be appro~imately represented by the equa-tion 1 as described hereabove, and the contrast can be evaluated as noted before. Thus, the value of ll~ was determined and is shown in Fig. 9.
36~
~able 1 2R Cmm) 2~ ~) I~Ain .
0.09 22 0.20 s 65 32 0.28 44 0.38 180 80 0.63 In Fig. g, the dotted line indicates the aperture number ~NA = 0.28) of the image fiber 11. ~t NAin = 0.63, 1/~ = 0.33 mm, and at NAin = 0.28, 1!~ = 0.26 mm. Thus, using the improve-ment ratio P as represented by equation ~2) above, the improve-ment is 21%. Alsoj when NAin = 0.09, 1/~ = 0.08. Thus, at ~Ain = 0.63, the improvement ratio P = 76%, and at NAin = 0.28, P = 69%. It has been confirmed that the ratio P is considerably high particularly when the incident angle is not more than the numerical aperture NA of the image fiber 11.
As can be seen from the above description, when the image transmission line of the invention is employed, -the contrast ofthe transmitted image can be improved and, furthermore~ the image transmission line o~ the invention has a simplified structure.
Thus, the image transmission line of the invention is readily applicable to conventional image transmission techniques and has excellent general-purpose properties. For example, when it is .:
36~
used as an image transmiss.ion line for a gastracamera or t~e like, a high contrast transmission image can be obtai.ned.
1 Fig. ~ is a graph.obtalned by standardizing experimental results; and Fig. 9 is a graph showing experimental results.
One image transmission :Line for use in the trans-mission of images or patterns comp.rises a number of optical fiber elements bundled together in the condition that they are lined up with each other, where the optical fiber elements are composed of a core portion having a high re-fractive index and a cladding portion surrounding the core portion and having a low refractive index, wherein, by the difference in refractive index between the core portion and the cladding portion, light incident into the core portion is subjected repeatedly to total reflection by the boundary between the core and cladding portions whereby the l$ light is transmitted through the core portion. The image thus transmitted is sent to the emission end where it is magnified by an image-receiving lens and converted into images suitable for direct reading, photographing with a 35 mm camera, and so forthO
At the emission end of the image transmission line 01, i.e., at the image-receiving side, as illustrated in Fig. 1, light A transmitted through the core portion 02 is subiected to Frenel reflection and scattering by the emission end surface 03, producing noise light B. Thus, information containing light is mixed with noise light B, leading to a reduction in the contrast of the transmitted image. This phenomenon may also occur at the incident end.
36~
1 In the case of light B incident into the core portion 1, as shown in Fig~ lA, if the incident angle of the ligh-t B
is larger than the aperture number which is determined b~
the s-tructure of an optical fiber element 13, i.e., the critical angle which is determined by the difference in refractive index between the core portion la and the clad-ding portion 22, light B passes through the cladding portion 22 and leaks Erom the line. Also, iE there is an irreg-ularity (a) e.g., an air bubble, an impurity or the like, between the optical fiber elements, or in the boundary between the core portion 1 and the cladding portion 22, part of the leaked light is irregularily reflected, becoming noise light C which mixes with the information light trans-mitted through the core portion 1, thereby further reducing the contrast of the transmitted image. Furthermore, an irregularity (b) between the cladding portion and a metallic sleeve 14 provided at the incident end surface of the image transmission line will further increase the reduction in contrast of the transmitted image.
SUMMARY OF T~E INVENTION
The object of the invention is to overcome the above-described problems and to provide an image trans-mission line which permits transmission of high contrast images, etc. The present invention, therefore, relates to an image transmission line comprlsing a number of optical fiber elements bundled together in a condition such that they are aligned with.one another, characterized in that . ~
3~i~3 ] at least one of the incidents end surface and -the emission end surface of the image transmission line is provided with contrast improving means.
DETAILED DESCRIPTION OF TEIE PREFERRED EMBODI~qE~TS
____ Fig. 2 i9 a longitudinal sectional view of an embodiment of the image ~ransmission line of the invention.
A number of optical fiber elements 1 are bundled together such that they are aligned with each other to form an image transmission line 2. The image transmission line 2 is provided with an image-receiving plug 3 and an image side (camera) plug 4 at either end thereof. The image-receiving plug 3 and the plug 4 are further provided with an image-receiving lens 5 and a camera lens 6, respectively, at the top end thereof. At a top end surface 3a of the image~receiving plug 3, which is an emission end surface, commercially available AR Coat 7 (anti-reflection) is coated as a reflection-preventing membrane. Also, a top end surface 4a of the camera plug 4, which is an incident end surface, is coated with AR Coat 7. Thus, the reflection of the light reaching the top end surface 3a of the image-receiving plug 3 at the emission end is pro-vented, and no contamination of information light with noise light will occur. Moreover, since the reflection-preventing membrane enables the inhibition of repeated reflection between the image-receiving plug 3 and the image-receiving lens S and between the plug 4 and the camera lens 6, information light 36~
will not mix with noise light and~ therefore~ the contrast of the transmission image can be increasecl~
Pigs. 3~a) and 3(~b~ aTe a longitudinal sectional view and a perspective view, respectively, of an image-receiving pLug portion oF another embodiment of the image -transmission line of the inverl-tion.
In this embodiment, the reflection-preventing membrane is not coated directly on the top end surface of either the image-receiving plug or the source plug, but it is first pro-vided on the outer surface of a glass plate 8 made of quartz, for example, by coa-ting AR Coat, and the glass plate 8 with the reflection-preventing me~brane provided -thereo-n is then adhered and fixed to the top end surface of the image-receiving plug or the source-side plug through a liquid ~matching oil) having a refractive index which is equal or nearly equal to the re-fractive index oE the core portion of the optical fiber element.
Ill this adhesion-fixation procedure, when a hole or holes 9 are bored in the image-receiving plug 3 in the longitudinal direction thereof as illustrated in Fig. 3~b) and an adhesive is injected into the hole 9, the glass plate can be firmly adhered and the adhesion strength can be increased. Also, a glass plate can be provided at the source plug side although the above explanation has been made with respect to an embod~men-t where the glass plate is provided at the image-receiving plug side Such provision of the reflection-preventing membrane 36~
on the glass plate 8 can produce th.e same results as in the above-described ~embodiment, in which the reflection-preventi.ng membrane is coated directly on the top end sur:face of -the image-receiving or source-side plug.
The contrast-improving e-ffect in the image transmission line of the invention will hereina-fter be described by re:ference to the following experiment.
In an experiment, as illustrated in Fig. 4, a diffuse light source having a uniform surface brightness and having a diameter~ D ~= 2R) , of 65 mm was employed, and, at a distance Q ~lll mm) from the diffuse light source, an image fiber 11 (aperture number, NA: 0.28) was placed. The aperture number of the incident light, NAin, was set to 0.28, so as to agree with that of the image fiber ll. A glass plate with AR Coat coa-ted thereon was adhered and fixed to the image fi.ber 11 at the image-receiving side thereof in the same manner as shown in Fig. 3.
In this condition, a knife edge 12 was placed at the incident end sur-face of the image fiber 11, and the image of the knife edge 12 was scanned in a direction x, perpendicular to the knife edge 12 at the image-receiving side, which was the emission end surface and the received light level E was measuTed. The value of the light level E was standardized to obtain a curve as shown in Fig. 5. This curve can be approximately represented by equa-tion ~l) as described hereinafter, and the contras-t can be evalu-ated by the ~radient o~ the approximate straight line at the :' ' ' 3~
rising zone (see Text No. 1086 of the Japanese Electronic Communication Association ~eeting '81). Thusl the value of 1/~ (Fig. 5) was determined and the contrast was evaluated using the value 1/~.
x < 0 1/2 e~
X < 1 - 1/2 e~~XX (1) 'I'he value 1/~ of the ~resent image transmission line to which the glass plate with AR Coat provided thereon was fitted was 0.15 mm, whereas, on the other hand, in the con-ventional image transmission line with no such glass plate pro-vided thereto, the value of 1/~ was 0.26 mm. Thus, the improve-ment ratio, P, represented by the e~uation ~2) as described below, was 42%. This demonstrates that the contrast improving effect is considerably large.
p = (1/~ before improvement) ~ a'fter improvement) ~ before improvement) ~2) Fig. 6 is a longitudinal sectional view of an incident end portion of another embodiment of the image transmission line of the invention.
Between a camera lens 35 and the end of an optical fiber element 13 at the incident end portion of an image transmission line I is provided a hood 36 as a member for controlling the maximum incident angle of the incident light to not more than the critical angle. The hood 36 ~s secured to a metallic sleeve ,C~36~
14. In the hood 36 i5 bored a tapered hole which is divergent toward the top end thereof. The taper determines the maximum incident angle of the incident light~ Of the light rays inci-dent into the image transmission line I through -the camera lens 35, those ra.ys having an incident angle greater than the numerical apertuIeof the image transmission line I are prevented from enter-ing the image transmission line I by the hood 36, and only those rays having an incident angle less than the numerical aperture, i.e., les.s than a critical angle, are allowed to enter the image ~rans-mission line. Thus, all incident light is transmitted throughthe image transmission line I by repeated total reflection and, without contamination with noise light, infornati:on light can be transmitted; that is, high contrast images or the like can be transmitted to the emission end portion of the image transmission line I.
Fig. 7 is a longitudinal sectional view of the incident end portion of another embodiment of the image transmission line of the invention.
In an image transmission line I of this embodiment, the metallic sleeve 14 is not provided with a hood, but instead, a stopping ring 37 is provided as a stopping member in the camera lens 35. According to -the size of central hole diameter of the stopping ring 37, light rays incident upon the image transmission line I are limited to those rays having an incident angle less than the aperture number ~critical angle)~ permitting trans - 8 - ..
3~
mission of high contrast images or the like.
~ lereinafter, the effect obtained by con-trolling the incident angle to less -than the critical angle of the image transmission line at the incident end surface thereof will be exaplained by reference -to the following expe-riment.
In this e~periment, also illustrated by Fig. 4, by changing the diame-ter R of a diffuse light source 10 having uniform surface brightness, and without the provisîon of a hood 36 or a stopping ring 37 as described heTeinabove, the incident angle 20 to an image fiber ~numerical aperture NA = 0~28) was changed. The fiber was placed at a distance of lll mm from the light source 10. In this case, the relation between the dia-meter R, the incident angle 23, and -thenumerical aperture o-f the incident light NAin (= sin ~) was as shown in 'Iable 1. By placing a knife edge 12 at the incident end surface of the image fiber 11, the image of the knife edge 12 was scanned in a direc`
tion x perpendicular to the knife edge, and the received light level E was measured. The values of the light levels were standardized to obtain a curve as shown in Fig. 8.
The curve can be appro~imately represented by the equa-tion 1 as described hereabove, and the contrast can be evaluated as noted before. Thus, the value of ll~ was determined and is shown in Fig. 9.
36~
~able 1 2R Cmm) 2~ ~) I~Ain .
0.09 22 0.20 s 65 32 0.28 44 0.38 180 80 0.63 In Fig. g, the dotted line indicates the aperture number ~NA = 0.28) of the image fiber 11. ~t NAin = 0.63, 1/~ = 0.33 mm, and at NAin = 0.28, 1!~ = 0.26 mm. Thus, using the improve-ment ratio P as represented by equation ~2) above, the improve-ment is 21%. Alsoj when NAin = 0.09, 1/~ = 0.08. Thus, at ~Ain = 0.63, the improvement ratio P = 76%, and at NAin = 0.28, P = 69%. It has been confirmed that the ratio P is considerably high particularly when the incident angle is not more than the numerical aperture NA of the image fiber 11.
As can be seen from the above description, when the image transmission line of the invention is employed, -the contrast ofthe transmitted image can be improved and, furthermore~ the image transmission line o~ the invention has a simplified structure.
Thus, the image transmission line of the invention is readily applicable to conventional image transmission techniques and has excellent general-purpose properties. For example, when it is .:
36~
used as an image transmiss.ion line for a gastracamera or t~e like, a high contrast transmission image can be obtai.ned.
Claims (9)
1. An image transmission line, comprising; a plurality of optical fiber elements bundled together and aligned with each other, wherein at least one of the incident end surface and the emergent end surface of the image transmission line is provided with means for removing light rays reducing the contrast of the transmitted image.
2. The image transmission line as claimed in claim 1, where-in said means comprises a stopping member for controlling the maximum incident angle of incident light to a value not more than the numerical aperture of the image transmission line at the incident end surface thereof.
3. The image transmission line as claimed in claim 1, where-in said means comprises a reflection-preventing membrane provided at at least one of the incident end surface and the emergent end surface of the image transmission line.
4. The image transmission line as claimed in claim 2, said stopping member comprising an end piece fixed to an incident end surface of said transmission line, and having an angular surface encompassing a solid angle related to said maximum incident angle, and centered about said incident end surface.
5. The image transmission line as claimed in claim 2, said stopping member comprising a stop ring associated with a lens group arranged in front of said incident end surface of said transmission line.
6. The image transmission line as claimed in claim 3, wherein said membrane is applied directly onto at least one of said incident and emergent end surfaces.
7. The image transmission line as claimed in claim 3, wherein said membrane is applied to a glass plate, said plate being affixed to at least one end of said transmission line through a matching liquid.
8. An image transmission line, comprising; a plurality of optical fiber elements bundled together and aligned with each other, wherein at least one of the incident end surface and the emergent end surface of the image transmission line is provided with a reflection-preventing membrane.
9. An image transmission line, comprising; a plurality of optical fiber elements bundled together and aligned with each other, wherein the image transmission line is provided at the incident end portion thereof with aperture controlling means for controlling the maximum incident angle of incident light to a value not more than the numerical aperture of the image trans-mission line or less.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP95645/81 | 1981-06-20 | ||
| JP56095645A JPS57210302A (en) | 1981-06-20 | 1981-06-20 | Picture transmission line |
| JP56095646A JPS57210303A (en) | 1981-06-20 | 1981-06-20 | Picture transmission line |
| JP95646/81 | 1981-06-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1189369A true CA1189369A (en) | 1985-06-25 |
Family
ID=26436866
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000405399A Expired CA1189369A (en) | 1981-06-20 | 1982-06-17 | Image transmission line |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US4776667A (en) |
| EP (2) | EP0069870A1 (en) |
| AU (2) | AU560182B2 (en) |
| CA (1) | CA1189369A (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4776667A (en) * | 1981-06-20 | 1988-10-11 | Sumitomo Electric Industries, Ltd. | Image transmission line |
| US4953947A (en) * | 1986-08-08 | 1990-09-04 | Corning Incorporated | Dispersion transformer having multichannel fiber |
| NL8902295A (en) * | 1989-09-14 | 1991-04-02 | Philips Nv | Apparatus for scanning a document along an optical path. |
| US5394499A (en) * | 1992-12-28 | 1995-02-28 | Olympus Optical Co., Ltd. | Observation system with an endoscope |
| US5321251A (en) * | 1993-03-31 | 1994-06-14 | Eastman Kodak Company | Angled optical fiber filter for reducing artifacts in imaging apparatus |
| FR2732094A1 (en) * | 1995-03-22 | 1996-09-27 | Philips Eclairage | LIGHT GENERATOR FOR OPTICAL FIBERS |
| US5818996A (en) * | 1996-01-18 | 1998-10-06 | Axiom Analytical, Inc. | Fiber-optic coupled diffuse reflectance probe |
| US5815624A (en) * | 1996-08-30 | 1998-09-29 | Rosenberg; Gary J. | Optical fiber viewing apparatus |
| JP4071407B2 (en) * | 1999-11-08 | 2008-04-02 | 矢崎総業株式会社 | Optical connector sleeve and receptacle |
| JP2003315208A (en) * | 2000-10-20 | 2003-11-06 | Kazumasa Sasaki | Method and apparatus for measuring internal refractive index of optical fiber preform |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1347487A (en) * | 1962-02-14 | 1963-12-27 | Int Standard Electric Corp | Mounting for picture tube screens |
| FR1462229A (en) * | 1965-07-08 | 1966-04-15 | Compact optical field reduction device | |
| NL6612387A (en) * | 1966-09-02 | 1968-03-04 | ||
| US3907403A (en) * | 1969-07-28 | 1975-09-23 | Matsushita Electric Ind Co Ltd | Fibre-optics faceplate observable with high-intensity ambient illumination |
| SE362148B (en) * | 1972-04-20 | 1973-11-26 | Aga Ab | |
| US3780979A (en) * | 1972-05-12 | 1973-12-25 | Clinitex Inc | Adjustable fundus illumination |
| DE2455221C3 (en) * | 1974-11-21 | 1979-03-08 | Siemens Ag, 1000 Berlin Und 8000 Muenchen | Optical system |
| JPS6012603B2 (en) * | 1976-02-23 | 1985-04-02 | 富士写真光機株式会社 | optical fiber bundle |
| JPS55135805A (en) * | 1979-04-12 | 1980-10-23 | Olympus Optical Co Ltd | Optical fiber bundle for bar-form image transmission |
| JPS55138434A (en) * | 1979-04-17 | 1980-10-29 | Olympus Optical Co | Hard endoscope |
| US4776667A (en) * | 1981-06-20 | 1988-10-11 | Sumitomo Electric Industries, Ltd. | Image transmission line |
| JPS60253428A (en) * | 1984-05-30 | 1985-12-14 | 住友電気工業株式会社 | Fiberscope with bending mechanism |
| AU5538986A (en) * | 1986-04-01 | 1987-10-08 | Amalgamated Wireless (Australasia) Limited | Optical fibre |
-
1982
- 1982-06-14 US US06/387,896 patent/US4776667A/en not_active Expired - Fee Related
- 1982-06-15 EP EP82105245A patent/EP0069870A1/en not_active Ceased
- 1982-06-15 EP EP85101575A patent/EP0159481A1/en not_active Withdrawn
- 1982-06-17 CA CA000405399A patent/CA1189369A/en not_active Expired
- 1982-06-18 AU AU84982/82A patent/AU560182B2/en not_active Ceased
-
1987
- 1987-02-27 AU AU69573/87A patent/AU599959B2/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| AU8498282A (en) | 1983-01-06 |
| US4776667A (en) | 1988-10-11 |
| AU599959B2 (en) | 1990-08-02 |
| AU6957387A (en) | 1987-06-11 |
| EP0069870A1 (en) | 1983-01-19 |
| AU560182B2 (en) | 1987-04-02 |
| EP0159481A1 (en) | 1985-10-30 |
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| MKEX | Expiry |