US4089010A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Display circuit for a camera
Assignee: Canon Inc
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Filing: 1976-09-30
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Granted: 1978-05-09
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Expires: 1996-09-30
Abstract
Abstract A photographing information display circuit for a camera which performs digital computation of information relative to exposure, etc. and displays the computed digital values. The display of the digital value computed is effected through an analog display circuit such as a meter circuit by an extremely simplified circuit arrangement, without using any D-A conversion circuit such as a ladder circuit or the like. The invented display circuit arrangement minimizes the electric power requirement for display to solve the problem of electric power consumption for display in small-sized camera.
Inventors
- 👤 Tadashi Ito
- 👤 Nobuaki Sakurada
- 👤 Masaharu Kawamura
- 👤 Nobuhiko Shinoda
- 👤 Fumio Ito
- 👤 Hiroyashu Murakami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 04:10
CPC Classifications
G; G03; G03B; G03B17/00; G03B17/18; G03B17/20
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
86 words
A display circuit for a camera comprising: (a) an exposure information producing circuit for producing a digital value corresponding to exposure information; (b) a storing means for storing the digital value produced by said exposure information producing circuit; (c) a pulse signal producing circuit coupled to said storing means for producing a pulse signal with a duty cycle corresponding to the digital value produced by said exposure information producing circuit; and (d) a meter coupled to said pulse signal producing circuit for displaying the exposure information.
Claim 2
Dependent Claim
86 words
A display circuit for a camera comprising: (a) an exposure information producing circuit for producing a digital value corresponding to exposure information; (b) a storing means for storing the digital value produced by said exposure information producing circuit; (c) a pulse signal producing circuit coupled to said storing means for producing a pulse signal with a duty cycle corresponding to the digital value produced by said exposure information producing circuit; and (d) a meter coupled to said pulse signal producing circuit for displaying the exposure information.
Claim 3
Dependent Claim
107 words
A display circuit according to claim 1 in which said pulse signal producing circuit comprises: a pulse generating means for producing a pulse in a preset cycle; a counter means for counting the pulses from said pulse generating means in a predetermined cycle; a comparison circuit for comparing the digital value from said exposure information producing circuit with a value counted by said counter means which inverts its output signal when said digital value and said counted value reach a preset relation to each other, so that said comparison circuit produces a pulse with a duty cycle corresponding to the digital value stored in the storing means.
Claim 4
Dependent Claim
106 words
A display circuit for a camera comprising: (a) an exposure information producing circuit for producing a digital value corresponding to exposure information; (b) a storing means for storing the digital value produced by said exposure information producing circuit; (c) a pulse signal producing circuit coupled to said storing means for producing a pulse signal with a duty cycle corresponding to the digital value produced by said exposure information producing circuit; (d) an integrating circuit coupled to said pulse signal producing circuit for integrating the pulse signal from said pulse signal producing circuit; and (e) a meter connected to said integrating circuit for displaying the exposure information.
Claim 5
Dependent Claim
106 words
A display circuit for a camera comprising: (a) an exposure information producing circuit for producing a digital value corresponding to exposure information; (b) a storing means for storing the digital value produced by said exposure information producing circuit; (c) a pulse signal producing circuit coupled to said storing means for producing a pulse signal with a duty cycle corresponding to the digital value produced by said exposure information producing circuit; (d) an integrating circuit coupled to said pulse signal producing circuit for integrating the pulse signal from said pulse signal producing circuit; and (e) a meter connected to said integrating circuit for displaying the exposure information.
Claim 6
Dependent Claim
107 words
A display circuit according to claim 3 in which said pulse signal producing circuit comprises: a pulse generating means for producing a pulse in a present cycle; a counter means for counting the pulses from said pulse generating means in a predetermined cycle; a comparison circuit for comparing the digital value from said exposure information producing circuit with a value counted by said counter means which inverts its output signal when said digital value and said counted value reach a preset relation to each other, so that said comparison circuit produces a pulse with a duty cycle corresponding to the digital value stored in the storing means.
Claim 7
Dependent Claim
80 words
A display circuit for a camera comprising: (a) an exposure information producing circuit for producing a digital value corresponding to exposure information; (b) a storing means for storing the digital value produced by said exposure information producing circuit; (c) a pulse signal producing circuit coupled to said storing means for producing pulses in time series according to the digital values stored in the storing means, and (d) a meter coupled to said pulse producing circuit for displaying the exposure information.
Claim 8
Dependent Claim
80 words
A display circuit for a camera comprising: (a) an exposure information producing circuit for producing a digital value corresponding to exposure information; (b) a storing means for storing the digital value produced by said exposure information producing circuit; (c) a pulse signal producing circuit coupled to said storing means for producing pulses in time series according to the digital values stored in the storing means, and (d) a meter coupled to said pulse producing circuit for displaying the exposure information.
Claim 9
Dependent Claim
25 words
A display circuit according to claim 5 in which said camera comprises an integrating circuit connected between said pulse signal producing circuit and said meter.
Claim 10
Dependent Claim
73 words
A display circuit for a camera comprising: (a) an exposure information producing circuit for producing a digital value corresponding to exposure information; (b) a storing means for storing the digital value produced by said exposure information producing circuit; (c) a pulse signal producing circuit for serially supplying pulses corresponding to said digital value stored in the storing means; and (d) a meter coupled to said pulse signal producing circuit for displaying exposure value.
Claim 11
Dependent Claim
73 words
A display circuit for a camera comprising: (a) an exposure information producing circuit for producing a digital value corresponding to exposure information; (b) a storing means for storing the digital value produced by said exposure information producing circuit; (c) a pulse signal producing circuit for serially supplying pulses corresponding to said digital value stored in the storing means; and (d) a meter coupled to said pulse signal producing circuit for displaying exposure value.
Claim 12
Dependent Claim
25 words
A display circuit according to claim 7 in which said camera comprises an integrating circuit connected between said pulse signal producing circuit and said meter.
References Cited (Backward Citations)
US3651744A
Cited
US4006484A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-05-08 | 1981-11-07 | 1982-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-08 | 1985-11-07 | 1986-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-08 | 1989-11-07 | 1990-05-09 | $7700.00 | Window Closed / Lapsed |