Image pickup device

[Detailed Description of the Invention]

improvement Kll of the imaging device with which the present invention used image sensors, such as COD, -- it carries out. O from which the optimal accumulation time is obtained especially and a picture with little Gaya is obtained and which is what is related as for Imaging device fllHc Generally in solid-state image sensing devices, such as COD, the noise ingredient Dangerous current nonuniformity to the signal electric charge at the time of president accumulation is dominant. Since the above-mentioned 1lifIIER nonuniformity increases in proportion to accumulation time, in order to escape this problem by fixing slight longest accumulation time to eye short Or beforehand in 0, therefore the conventional image pick-up Takako art with the fault that substantial sensor sensitivity will fall with accumulation time, The photography limit was suppressed low more than needed. Therefore also had a fault which enters as a noise ingredient which dark current Muff cannot disregard too, when used under comparatively high temperature conditions. An object of the present invention is to provide an imaging device with little camera shake etc. from thing K for which it enables it to opt the limit of accumulation time (image pick-up speed) the optimal at the same time the present invention removes the fault of the above-mentioned conventional technology. Therefore, by the present invention, to ill 11 means for controlling the accumulation time in an image sensor, a dark current detection means is established, and it acts as a missing person of the print-out of the above-mentioned dark current detection means, and it constitutes so that the accumulation time of an image sensor may be controlled by this dark current parameter. As for this, a suitable fk signal level becomes as [ obtain / to 11 environment and change of photographic subject 'N11 / signal level / always ]. The present invention is explained to Magnificence based on an example below. Drawing 1 is a characteristic figure showing the temperature dependence of Hata of a common solid Shooting element, and a part for phi according [ a part for Hata according / one in a figure / to dark current nonuniformity and 2 ] to an amplifier noise and 6 show the S/N 4I nature by both composition. the noise ingredient according to dark current nonuniformity like a figure -- accumulation time T+ -- comparing with an amplifier noise from per NTO -- a large -- it comes to have influence, and they are the main factors which determine 34, so that accumulation time becomes long. Generally, since sensitivity is proportional to S/N, in such long accumulation time, Company feeling vertical falls considerably. Therefore, it is preferred rather to lengthen accumulation time for the signal electric charge more than a predetermined level in such a field at a Be proud sake (ゝ0). Since it constitutes from a time of there being such a Cumulative segment of time in view of an above-mentioned point in the present invention so that accumulation time may not be extended but the gain of vIL Fit amplifier may be increased, while To feel drowsy <> can do Light sensitivity also to a low-intensity photographic subject A good picture with little whole surface Copying by 1 camera shake etc. can be obtained. With the block diagram showing the example of the present invention, Drawing 2 Taylor the electric charge from predetermined Tatsu former partial provided in some below-mentioned image sensors 10 10', and four in To ru 0 figure integrates the integration circuit as a dark current detection means with it. The conversion (Ro) way where 5 may output the integration circuit output to the predetermined function like the 6th illustration as To obey Yoshinobu item TINTO, and 6 are charge conversion methods, such as SPC, and the means detects the amount of former which should enter into image sensor 10. The output of the below-mentioned image sensor 10 may be used instead of using the SPC. The subformer circuit which outputs seven companies of appearance information E meetings edited by a basis companion to the output bit of the SPC, The drive-way where 09 which is a control circuit which controls 8 according to a program which mentions below the widening rate (gain) of amplifier 11 which widens the output of accumulation time TINT in image sensor 10 and image sensor 10 of the # 1 yuan based on a circuit output is controlled by the control circuit, The output amplifier and 12 are Tagata ends the image sensor with which r+N dishes of time is controlled by the drive (Ro) way 9 by Accumulation 11 of the picture from -m accumulation start switch SW[-0NL and The 10, and 11. In the program figure showing an example of a control program [ in / in Drawing 4 / control circuit 8 ], a horizontal axis is the logarithm of accumulation time, a vertical axis is a gain of amplifier 11, and a KvFim party-way output, a control program curve [ in / in 15 / temperature T1 of Drawing 6 ], and 14 show the control program figure line which can be set to the 3rd illustration temperature T. At the present invention, it is Like (control which only increases accumulation time TINT with increase of Ev cannot be performed, but the S/h characteristic can always be acquired by changing an amplifier gain.) of the 4th illustration. accumulation time 1 l-TO shrine predetermined with the present invention again -- until -- controlling accumulation time If this is exceeded, it constitutes so that accumulation time may be made into - and a law and only an amplifier gain may be IIJiKl(ed) one time (0 which also breaks the advantage it becomes A 4 Khumu is simplified very much by - Ruri, and easy to constitute of a side 1141Igl way again). since account accumulation time T+Nvo of mij is changed by dark current detector circuit 40 output in the present invention -- always -- control formation of Most -- a sake -- going out -- a noise ingredient -- below a fixed ratio -- pushing -- having -- if (the - Excellent effect is acquired.) 0 which may compare the TI NTO information as a Conversion 1 way output, and may input still into control circuit 8 as a tJ voltage level and which may be carried out and may be inputted as a - hood pattern -- again It is A (being what is restricted to a turn ri 0 which is not again) like the 4th illustration of Fi as pull gram music -. Taking gI! as an element, not only COD but the thing which may be BBD and MOS comes out with a roar -- certain 0 -- the proper method that in addition the program pattern like the 4th illustration in control circuit 8 is conventionally publicly known -- formation To -- Seduction. 0 [ for example, ] which can be obtained by Behavior using pattern-generator Some B ROM-?PL, A (programmable logic array), etc. -- again The S/N characteristic outstanding on Melancholy ili& degree conditions can be acquired until high mK results not only in the imaging device #i image sensor of the present invention but in the line sensor for ranging, etc. from those optical part applicable with The, and low temperature. Since it is not necessary to extend accumulation time to a low-intensity photographic subject more than needed, it is hard to produce the whole surface deflection by vibration of Shooting #c11Il, etc. Therefore, when Noodle image poor t of the present invention is used as a camera, especially the effect is large.

[Brief Description of the Drawings]

It is a figure showing an example of the being [ can set the mimetic diagram in which Drawing 1 shows the accumulation time dependency of a general image pick-up this child's Hata the block diagram in which Drawing 2 shows an example of the composition of the present invention, and Drawing 6 to the conversion % figure of 2nd illustration conversion side way 5, and / grotesque Gutem / Drawing / 4 ] exposure curve between photographic subject luminosity, accumulation time, and output gain 9. 4 [ ..... Control circuit / 9 / .. Image pick-up start switch / .. ---drive 4 way SW .. Lu ] ..... Dark current detection means 5, a fist, a fist, and conversion circuit 6 ..... Photographic subject jlf detection means 7 ..... Side Optical enclosure 8 Applicant for a patent Canon~, Inc.-1 and 1