Focusing device for optical instruments

Claim 2

A focusing device for optical instruments comprising: ray projection means for projecting a narrow beam of light on an object; ray receiving means offset from said ray projection means including at least one ray receiving optical system for transmitting therethrough radiation from an object and capable of forming an image of the portion of said object illuminated by said ray projection means; photoelectric converter means including at least two photoelectric elements functioning substantially individually and contiguous with each other along a straight line boundary, said converter means being arranged to receive radiation through said ray receiving optical system from the illuminated portion of said object to form an illuminated image thereof on said photoelectric elements; masking means including an opening to control the effective light receiving surfaces of said at least two photoelectric elements, said opening being shaped and so disposed relative to said straight line boundary as to change the ratio of the outputs of said at least two photoelectric elements caused by the illuminated image of the object in response to the position of said image on their said effective light receiving surfaces; image forming means including at least one image forming optical system having an optical axis at least approximately parallel to the optical axis of said ray receiving means and adjustable in the direction along said first-mentioned optical axis; and control means including a circuit having at least said photoelectric elements of said photoelectric converter means and including an amplifier the input of which receives the output of said circuit; said control means being operatively connectable with said image forming means, and arranged to produce when so connected a control signal for adjusting said adjustable image forming optical system to focus on the object.

Claim 3

A focusing device according to claim 1, wherein said control means includes drive means for driving said image forming optical system of said image forming means in the direction along the optical axis thereof.

Claim 4

A focusing device according to claim 2, wherein said drive means includes a servomotor.

Claim 5

A focusing device according to claim 1, wherein said control means includes indicator means for indicating the focused condition.

Claim 6

A focusing device according to claim 4, wherein said indicator means includes an indicator member capable of display in at least a portion of a viewfinder.

Claim 7

A focusing device according to claim 5, wherein said indicator member comprises a meter which can display at least a portion of the needle thereof in said viewfinder.

Claim 8

A focusing device according to claim 4, wherein said indicator means includes at least one luminous member adapted to indicate the focused condition by flashing.

Claim 9

A focusing device according to claim 7, wherein said indicator means includes means for controlling the flashing of said luminous member, said latter means being adapted to selectively flash one of two or more luminous members in accordance with a control signal from said control means.

Claim 10

A focusing device according to claim 4, wherein said indicator means can simultaneously indicate the information representing the set position of said adjustable image forming optical system and the information representing a position corresponding to the object distance.

Claim 11

A focusing device according to claim 4, wherein said indicator means includes means for approximately indicating the depth of field.

Claim 12

A focusing device according to claim 1, wheRein said control means is set so that the output thereof assumes a predetermined value when said image forming optical system is in focused condition.

Claim 13

A focusing device according to claim 11, wherein said photoelectric converter means can detect the magnitude and direction of the difference between the object distance and the set position of said image forming optical system, and said control means includes means capable of indicating said difference in a viewfinder.

Claim 14

A focusing device according to claim 1, wherein said control means includes means associated with said image forming means to associate movement of said adjustable image forming optical system with movement of at least one portion of said ray receiving optical system in a predetermined relationship.

Claim 15

A focusing device for optical instruments comprising: a radiation source; projector means including optical means for projecting a narrow beam of radiation toward an object; ray receiving means offset from said projector means including at least one ray receiving optical system for transmitting therethrough radiation from said object and capable of forming an image of the portion of said object illuminated by said projector means said ray receiving optical system including means for elongating said image in a direction transverse to the direction of offset of said ray receiving means from said projector means; photoelectric converter means having a light-receiving face and including at least two photoelectric elements functioning substantially individually and contiguous with each other along a straight line boundary disposed parallel to said direction of offset of said receiving means and transverse to the elongation of said image by said elongating means, said converter means being arranged to receive radiation through said ray receiving optical system from the illuminated portion of said object to form an illuminated image thereof on said photoelectric elements that extends across both of said two elements regardless of the position of said image along said boundary line; masking means disposed in contact with said light receiving face of said at least two photoelectric elements and including an opening to control the effective light receiving surfaces of said at least two photoelectric elements, the opening being so formed that the ratio of the outputs of said at least two photoelectric elements, will vary essentially in response to the position of said image on said effective light receiving surfaces; image forming means including at least one image forming optical system adjustable in the direction along the optical axis thereof; and control means including a circuit having at least said photoelectric elements of said photoelectric converter means and including an amplifier the input of which receives the output of said circuit; said control means being operatively connectable with said image forming means, and producing a control signal for adjusting said adjustable image forming optical system to focus on the object.

Claim 16

A focusing device for optical instruments comprising: a radiation source; projector means including optical means for projecting a narrow beam of radiation toward an object; ray receiving means offset from said projector means including at least one ray receiving optical system for transmitting therethrough radiation from said object and capable of forming an image of the portion of said object illuminated by said projector means said ray receiving optical system including means for elongating said image in a direction transverse to the direction of offset of said ray receiving means from said projector means; photoelectric converter means having a light-receiving face and including at least two photoelectric elements functioning substantially individually and contiguous with each other along a straight line boundary disposed parallel to said direction of offset of said receiving means and transverse to the elongation of said image by said elongating means, said converter means being arranged to receive radiation through said ray receiving optical system from the illuminated portion of said object to form an illuminated image thereof on said photoelectric elements that extends across both of said two elements regardless of the position of said image along said boundary line; masking means disposed in contact with said light receiving face of said at least two photoelectric elements and including an opening to control the effective light receiving surfaces of said at least two photoelectric elements, the opening being so formed that the ratio of the outputs of said at least two photoelectric elements, will vary essentially in response to the position of said image on said effective light receiving surfaces; image forming means including at least one image forming optical system adjustable in the direction along the optical axis thereof; and control means including a circuit having at least said photoelectric elements of said photoelectric converter means and including an amplifier the input of which receives the output of said circuit; said control means being operatively connectable with said image forming means, and producing a control signal for adjusting said adjustable image forming optical system to focus on the object.

Claim 17

A focusing device for an optical instrument utilizing rays from an object to be focused, comprising: a ray receiving optical system for transmitting therethrough rays from said object and capable of forming an image of said object; photoelectric converter means including at least two photoelectric elements functioning substantially individually and contiguous with each other along a straight line boundary, said converter means being arranged to receive said rays through said ray receiving optical system from the object to form an image thereof on said photoelectric elements that extends across both of said two elements and to produce an electrical signal corresponding to the relative amounts of said rays received on said two photoelectric elements respectively; masking means disposed in front of said photoelectric elements so as to restrict the area thereof on which said rays from said object impinge on said photoElectric elements, and shaped to control the relative amounts of said rays impinging on the said two photoelectric elements respectively in such a manner that the electrical ratio signal of said photoelectric converter means is varied in accordance with the position of said image thereon; a focusing optical system adjustable in the direction along the optical axis thereof to focus the object; and control means connected to said photoelectric converter means to receive the electrical signal thereof and operatively connectable with said focusing optical system to detect a position of said focusing optical system so as to produce a control signal for adjusting said adjustable focusing optical system to focus on the object.

Claim 18

A focusing device for an optical instrument utilizing rays from an object to be focused, comprising: a ray receiving optical system for transmitting therethrough rays from said object and capable of forming an image of said object; photoelectric converter means including at least two photoelectric elements functioning substantially individually and contiguous with each other along a straight line boundary, said converter means being arranged to receive said rays through said ray receiving optical system from the object to form an image thereof on said photoelectric elements that extends across both of said two elements and to produce an electrical signal corresponding to the relative amounts of said rays received on said two photoelectric elements respectively; masking means disposed in front of said photoelectric elements so as to restrict the area thereof on which said rays from said object impinge on said photoElectric elements, and shaped to control the relative amounts of said rays impinging on the said two photoelectric elements respectively in such a manner that the electrical ratio signal of said photoelectric converter means is varied in accordance with the position of said image thereon; a focusing optical system adjustable in the direction along the optical axis thereof to focus the object; and control means connected to said photoelectric converter means to receive the electrical signal thereof and operatively connectable with said focusing optical system to detect a position of said focusing optical system so as to produce a control signal for adjusting said adjustable focusing optical system to focus on the object.

Claim 19

A focusing device according to claim 15, wherein said masking means has an opening for controlling the radiation incident on said photoelectric elements and said opening is adapted to control the quantity of incident radiation in accordance with the position of the image formed on said photoelectric elements, said position being variable along the boundary between said elements in accordance with the object distance.

Claim 20

A focusing device in accordance with claim 15, wherein said photoelectric converter means produces an output providing information corresponding only to object distance.

Claim 21

A focusing device according to claim 17, wherein said control means includes detector means for detecting the set position of said adjustable image forming optical system to produce information corresponding to said set position.

Claim 22

A focusing device according to claim 18, wherein said control means includes comparator means for comparing the information representing the object distance and the information representing the set position of said adjustable image forming optical system to produce a control signal representing the magnitude and direction of the difference between said two types of information.

Claim 23

A focusing device according to claim 15, wherein said ray receiving means includes at least one optical element for elongating the radiation image of the illuminated portion of said object in a direction substantially perpendicular to said straight line boundary between said photoelectric elements.

Claim 24

A focusing device according to claim 20, wherein said optical element comprises a cylindrical lens.

Claim 25

A focusing device for optical instruments with a view finder comprising: a ray receiving optical system for transmitting therethrough rays from an object and capable of forming an image of said object; photoelectric converter means including at least two photoelectric elements functioning substantially individually and contiguous with each other along a straight line boundary, said converter means being arranged to receive said rays through said ray receiving optical system from said object to form an image thereof on said photoelectric elements that extends across both of said two elements and produce an electrical ratio signal corresponding to the amounts of said rays respectively received on said two photoelectric elements; masking means disposed on the photoelectric elements thereof so as to restrict the area on which said rays from said object impinge and shaped to control the relative amounts of said rays impinging respectively on said photoelectric elements according to the position of said image a focusing optical system adjustable in the direction along its optical axis to focus on the object; control means connected to said photoelectric converter means to receive the electrical signal thereof and operatively connectable with said focusing optical system to detect a position of said focusing optical system so as to produce a control signal for adjusting said adjustable focusing optical system to focus on the object; means for indicating the status of focus including a detecting member for detecting the position of said focusing optical system and an indicating member for indicaTing the position detected by said detecting member, said indicating member being positioned in the path of said view finder of said optical instrument thereby to indicate the status of focus in said view finder.

Claim 26

A focusing device for optical instruments with a view finder comprising: a ray receiving optical system for transmitting therethrough rays from an object and capable of forming an image of said object; photoelectric converter means including at least two photoelectric elements functioning substantially individually and contiguous with each other along a straight line boundary, said converter means being arranged to receive said rays through said ray receiving optical system from said object to form an image thereof on said photoelectric elements that extends across both of said two elements and produce an electrical ratio signal corresponding to the amounts of said rays respectively received on said two photoelectric elements; masking means disposed on the photoelectric elements thereof so as to restrict the area on which said rays from said object impinge and shaped to control the relative amounts of said rays impinging respectively on said photoelectric elements according to the position of said image a focusing optical system adjustable in the direction along its optical axis to focus on the object; control means connected to said photoelectric converter means to receive the electrical signal thereof and operatively connectable with said focusing optical system to detect a position of said focusing optical system so as to produce a control signal for adjusting said adjustable focusing optical system to focus on the object; means for indicating the status of focus including a detecting member for detecting the position of said focusing optical system and an indicating member for indicaTing the position detected by said detecting member, said indicating member being positioned in the path of said view finder of said optical instrument thereby to indicate the status of focus in said view finder.

Claim 27

A focusing device for optical instruments provided with a viewfinder, comprising: ray projecting means for projecting a narrow beam of light in a predetermined direction toward an object to be focused on; ray receiving means offset from said ray projection means including at least one ray receiving optical system for transmitting therethrough radiation from the object and capable of forming an image of the portion of said object illuminated by said ray projection means; photoelectric converter means including at least two photoelectric elements functioning substantially individually and contiguous with each other along a straight line boundary, said converter means being arranged to receive radiation through said ray receiving optical system from the illuminated portion of said object to form an illuminated image thereof on said photoelectric elements and produce an output signal corresponding to the relative amounts of light of said formed image on said respective photoelectric elements; radiation receiving control means disposed on the photoelectric elements in order to control the amount of radiation light impinging on said photoelectric elements and shaped so as to vary the output signal of said photoelectric converter means in accordance with the position of said image thereon; focusing optical means adjustable in the direction along the optical axis thereof to vary the focus condition; control means connected to said photoelectric converter means to receive the output signal thereof and operatively connectable with said focusing optical means to detect a signal representing the current position of said focusing optical means so as to compare the both signals and produce a control signal for adjusting said focusing optical means to focus on the object; and focus indicating means adapted to be indicatable in the viewfinder of the optical instrument in accordance with the adjustment of said focusing optical means.

Claim 28

A focusing device for optical instruments provided with a viewfinder, comprising: ray projecting means for projecting a narrow beam of light in a predetermined direction toward an object to be focused on; ray receiving means offset from said ray projection means including at least one ray receiving optical system for transmitting therethrough radiation from the object and capable of forming an image of the portion of said object illuminated by said ray projection means; photoelectric converter means including at least two photoelectric elements functioning substantially individually and contiguous with each other along a straight line boundary, said converter means being arranged to receive radiation through said ray receiving optical system from the illuminated portion of said object to form an illuminated image thereof on said photoelectric elements and produce an output signal corresponding to the relative amounts of light of said formed image on said respective photoelectric elements; radiation receiving control means disposed on the photoelectric elements in order to control the amount of radiation light impinging on said photoelectric elements and shaped so as to vary the output signal of said photoelectric converter means in accordance with the position of said image thereon; focusing optical means adjustable in the direction along the optical axis thereof to vary the focus condition; control means connected to said photoelectric converter means to receive the output signal thereof and operatively connectable with said focusing optical means to detect a signal representing the current position of said focusing optical means so as to compare the both signals and produce a control signal for adjusting said focusing optical means to focus on the object; and focus indicating means adapted to be indicatable in the viewfinder of the optical instrument in accordance with the adjustment of said focusing optical means.