JPS6125143B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a data capture device for a camera, and more particularly to a data capture device that automatically and appropriately controls data capture time. 2. Description of the Related Art Cameras are already available in which data such as the date of photography, day of the week, etc. are imprinted on each film frame when taking a photograph. By the way, when imprinting this data, the light emitting time of the data imprinting light emitter, such as a lamp or a light emitting diode, must be controlled in accordance with the type of film used.
That is, use a changeover switch to select in advance whether the film to be used is black and white or color, and its film sensitivity (ASA), and then set these in the data copying device. If you do not control the light emitting time of the light emitter, you will not be able to obtain data with the same density as on the screen. However, this setting operation is not only very troublesome, but also the method of controlling the light emitting time of the light emitting body by setting the film sensitivity and separating black and white film and color film is difficult when the data is imprinted from the back side of the film. (ASA)
Even if they are the same, the light transmittance of the film base is different between black and white film and color film, so it is not possible to obtain accurate light emission control time just by considering the film sensitivity and the selection of black and white film and color film. It is not possible. That is, according to sensitometry determined by the Japan Photographic Machinery Association, the density in photographs is expressed as shown in Table 1 below.

【table】

[Table] A density of 0.0 is completely transparent, and a light transmittance of 0.01 is the limit of surface visual acuity for slide projection.
In this way, every time the density value increases by 0.3, the density doubles and the light transmittance halves. The actual density values of each commercially available film are shown in Table 2 below.

[Table] Therefore, as can be seen from the above table, even if the film sensitivity is the same as ASA100, the density of both the black and white film and the color film is largely different. It is said that if the sensitivity of the film is the same, the sensitivity to light passing through the photographic lens is constant. However, it is known that the amount of light passing through the film varies depending on the thickness, transparency, etc. of the film base, as described above. Furthermore, as an extreme case of this density difference, for example, the density of Tri-X (trade name) film (ASA400) is 2.22, and the density of Sakura Color 400 (trade name) is 2.22.
The density of the film (ASA400) is 3.48. This means that even with the same film sensitivity, the transmittance of light with a density of 2.22 is 0.64%, as shown in Table 1 above, while the transmittance of light with a density of 3.48 is 0.034%, which means that light that has passed through the film is 0.034%. The difference in light transmittance is 18.8 times. Therefore, in order to properly control the exposure time of the data exposure emitter, in addition to the selection of whether the film is black and white or color and the film sensitivity, it is also necessary to take into consideration the light transmittance of the film base, that is, the density. In order to do this, at least three to four stages of switching selection means are required, which has the disadvantage that the switching setting operation becomes increasingly cumbersome. In view of the above-mentioned points, an object of the present invention is to receive the light transmitted through the film by a photoelectric conversion element during photographic exposure, and adjust the light emission time of the data recording light emitter according to the amount of light reaching the element. An object of the present invention is to provide a data recording device for a camera that automatically controls data recording to perform proper data recording. In other words, the amount of light transmitted through the film varies depending on the transparency of the film and the transmittance of the film base, so if the amount of transmitted light of the film used is photometered and the light emitting time of the data recording emitter is controlled using this, The light emission time can be appropriately controlled regardless of color, black and white film, and film sensitivity. The imprinting apparatus of the present invention was developed based on this viewpoint. Hereinafter, the present invention will be explained in detail with reference to an illustrated embodiment. As shown in FIG. 1, a shutter 3 is located in front of the film 2 loaded into the camera body 1.
is installed. A photographing lens 4 is disposed in front of it on the optical axis O of the photographing lens.
As is well known, when the shutter is released, the shutter 3 serves to open the exposure optical path and expose the film 2 to the photographic light that has passed through the photographic lens 4. The film 2 disposed behind the shutter 3 is disposed so as to correspond to a photographic image area 1a formed between the shutter 3 and the film 2, that is, a mask section formed on the body 1. This film is attached to the camera back cover 5 with springs 6a and 6b.
The pressure plate 7 elastically supported by the pressure plate 7 presses the back side of the pressure plate 7, thereby regulating the correct position of the film 2 in the front-rear direction. In this device, a light receiving hole 8 is provided in a part of the pressure plate 7 supported by the back cover 5 in this manner. At least one light-receiving hole 8 is bored in a portion of the pressure plate 7 corresponding to the film photographing area.
A photoelectric conversion element 9 made of, for example, CdS is arranged in the back cover 5 corresponding to the light receiving hole 8. Further, a window hole 10 for data recording is provided near one side edge of a portion of the pressure plate 7 corresponding to the photographic image area 1a, and behind this window hole 10, a back cover 5 is provided. A light emitting body 11 is arranged as appropriate. The light emitter 11 is composed of, for example, a lamp, and is connected to an electric circuit for data projection (see FIG. 2). In addition, this luminous body 1
A peripheral portion of a data plate 12 is arranged between the data plate 1 and the window hole 10. This data plate 12 has its center fixed to a shaft 13 that is rotatably supported by the back cover 5, and the data provided on its periphery is located between the light emitting body 11 and the window hole 10. I'm starting to do that. The outer end of the shaft 13 protrudes outward from the back cover 5, and a data dial 14 is fixed to the protrusion. Then,
By rotating this dial 14, desired data on the data plate 12 to be imprinted on the film 2 can be positioned between the light emitting body 11 and the window hole 10. Note that the light emitting body 11 is
It is surrounded by a hood (not shown) and is configured to accurately illuminate data. Also, inside the back cover 5, the light emitting body 11 is provided.
Electric circuit for data imprinting (see Figure 2)
is incorporated. Further, the camera to which the data copying device of the present invention is applied is a camera that employs an electric shutter, in which the main switch is closed by pressing the shutter button, and the shutter control circuit and data copying are activated. When a power source is connected to the electric circuit for use, the shutter 3 is opened. The electric circuit for data imprinting built into the camera back 5 is constructed as shown in FIG. 2, an example of which is shown in FIG. In FIG. 2, a control circuit for an electric shutter and a light emission time control circuit for a data recording light emitter 11 are connected to both ends of a power source E via a main switch SW. The above-mentioned shutter control circuit SC is a well-known circuit that includes a photometric light receiving element P such as CdS, and operates at the same time as the shutter 3 is opened, measures the light reflected from the subject, and measures the light reflected from the subject. Automatically determine the exposure amount. This shutter control circuit
A switching transistor TR ₁ is connected to _the output terminal of the SC.
Shutter closing magnet connected in series with
It is designed to control energization to Mg. That is, the switching transistor TR ₁ is
When the shutter is opened and the control circuit SC operates, it becomes conductive and excites the magnet Mg to restrain the shutter closing member and maintain the shutter in the open state. When the control circuit SC properly controls the exposure of the film, the switching transistor _TR1 is turned off, cutting off the current to the magnet Mg and closing the shutter. Note that a capacitor _C1 for preventing back electromotive force is connected to both ends of the magnet Mg. The light emission time control circuit operates by receiving a signal from the collector of the switching transistor _TR1 . That is, the above collector is connected to CMOS inverter IC ₁ .
Connected to each input terminal of IC ₆ . As is well known, CMOS inverters are
The inverter consists of a MOS IC that integrates a large number of MOSFETs (metal, oxide, semiconductor, field effect transistors) as elements, and has the characteristic that almost no power is consumed except during operation. There is. The output terminal of the above CMOS inverter IC ₁ is connected to one input terminal of the NAND gate IC ₂ ,
An oscillation pulse signal from a variable pulse signal oscillator OSC formed by an astable multivibrator is applied to the other input terminal of this NAND gate IC ₂ . The astable multivibrator constituting the pulse signal oscillator OSC is composed of CMOS inverters _IC4 , _IO5 , a capacitor _C2 , a resistor _R1 , and a photoelectric conversion element 9 formed of the CdS. That is,
A sufficiently large resistor R ₁ is connected to the input end of the CMOS inverter IC ₄ , and a photoelectric conversion element 9 and a capacitor C ₂ are connected to the input end and output end of the CMOS inverter IO ₅ , respectively. The resistor of the photoelectric conversion element 9 and the time constant circuit of the capacitor _C2 determine the pulse width and period of the oscillation pulse of the oscillator OSC. Then, this oscillation pulse signal is generated by the above NAND gate.
It passes through IC ₂ and is applied as a clock pulse to the electronic counter EDC via CMOS inverter IC ₃ . The above-mentioned counter EDC is well-known and consists of a flip-flop array, and the number of pulses counted by this counter EDC is determined by the decoder.
Each inverter IC ₀₁ ~ is read by the RDC into a decimal value and connected to the output end of the same decoder.
It is output to IC _0o and one of the resistors R ₀₁ to R _0o . Above inverter IC ₀₁ ~ IC _0o and resistor R ₀₁ ~
If the counter EDC has N bits, a maximum of 2 ^N -1 R _0o can be set. On the other hand, the output end of the CMOS inverter IC ₆ is connected to the input end of the CMOS inverter IC ₇ , and the output end of the inverter IC ₇ has a trigger for operating the light emission time control circuit of the data imprinting circuit. A differentiation circuit that generates a signal is connected. This differentiator circuit consists of capacitor C ₃ and resistor R ₂
The output pulse is applied to the input terminal of CMOS inverter IC ₈ for waveform shaping. _The output pulse for this trigger signal is generated when the switching transistor TR ₁ is turned from on to off, and its pulse width is T ₂ = K ₂・ C ₃・ R ₂ ( (see Figure 3) is generated at the output terminal of inverter IC ₈ . Note that K ₂ is a coefficient. The output of the above inverter IC ₈ is the CMOS inverter IC ₉ , IC ₁₀ , capacitor C ₄ , C ₅ , resistor R ₃
It is now being added to the monostable multivibrator consisting of i.e. inverter
The output end of IC ₈ is connected to CMOS through capacitor C ₄ .
Connected to the input end of inverter IC ₉ , CMOS
The output end of inverter IC ₉ is connected to the input end of CMOS inverter IC ₁₀ through capacitor _C5 . The output end of this inverter IC ₁₀ is a resistor
It is connected to the input end of the above inverter IC ₉ through _R3 . In addition, each resistor at the output end of the decoder RDC is connected to the input end of the inverter IC ₁₀ .
R ₀₁ to R _0o are connected. A light emitting circuit is connected to the output end of the light emitting time control circuit configured as described above. That is, the output of the control circuit is taken out from the output terminal of the inverter IC ₉ , and this output terminal is connected to the base of the transistor TR ₂ of the light emitting circuit through the resistor R ₄ . The light emitting circuit includes a switch across the transistor TR ₂ and the power source E.
It consists of a light emitter 11 and a series circuit of a transistor TR ₃ connected via SW. The above transistors TR ₂ and TR ₃ are connected together,
The collector of the transistor TR ₂ is connected to the positive terminal of the power source E together with one end of the light emitter 11 through a resistor R ₅ . The other end of the light emitting body 11 is connected to the collector of the transistor TR ₃ , and the emitter of the transistor TR ₃ is connected to the negative terminal of the power source E.
Connected via SW. In addition, the output end of the above inverter IC ₉ is
It is also connected to the input end of CMOS inverter IC ₁₁ . This CMOS inverter IC ₁₁ is similar to other
This circuit, together with CMOS inverters IC ₁₂ and IC ₁₃ , a capacitor C ₆ , a differentiation circuit consisting of a resistor R ₆ , and a resistor R ₇ , generates a reset signal for the counter EDC. That is, at the output terminal of the inverter IC ₁₁ , a capacitor C ₆ and a resistor are connected to generate a reset pulse signal.
A differential circuit _R6 is connected, and its differential pulse is applied to the input terminal of an inverter IC ₁₂ for waveform shaping. this inverter
The output terminal of IC ₁₂ is further applied to the input terminal of inverter IC ₁₃ , and the output terminal of inverter IC ₁₃ is connected to a resistor.
Connected to _R7 and also to the reset terminal of the counter EDC. The reset pulse signal generated by this reset circuit is transmitted to the light emitter 11.
It is created in connection with the operation of turning off transistor TR ₂ when data imprinting is completed, and the pulse width of the pulse signal is
T ₄ is, as shown in Figure 3, T ₄ = K ₄・C ₆・
Determined by R ₆ . Note that K ₄ is a coefficient. The above is the configuration of the light emission time control circuit of the data imprinting light emitter 11. Next, the operation of this light emission time control circuit will be explained with reference to the sequence time chart shown in FIG. If you press the shutter button now to start photographing the subject, the shutter will open and at the same time the main switch SW will close and the shutter control circuit will close.
When the SC is activated, the transistor _TR1 is turned on and the magnet Mg is energized, and this excitation opens the shutter and exposes the film 2 (see Figure 1). When this exposure is started, the light transmitted through the film 2 passes through the light receiving hole 8 and enters the photoelectric conversion element 9. The amount of light received by this photoelectric conversion element 9 and transmitted through the film is:
Since it is proportional to the light transmittance of the film, the photoelectric conversion element 9 shows a change in resistance value corresponding to this. Then, the pulse signal oscillator OSC generates a constant cycle pulse signal with a pulse width _T1 determined by the resistance value of the photoelectric conversion element 9 and the time constant of the capacitor _C2 . That is, for example, if the resistance value of the photoelectric conversion element 9 is Rcds, this pulse signal is generated as a pulse signal with a pulse width T ₁ =K ₁ ·Rcds ·C ₂ as shown in FIG. This pulse signal passes through the NAND gate IC ₂ , which is opened by turning on the transistor TR ₁ , and
It passes through inverter IC ₃ and is applied as a clock pulse to counter EDC, where it is counted. The pulses counted by this counter EDC are read as a _decimal value by a decoder RDC, and are applied to the resistance corresponding to the read value among the resistances R ₀₁ to _{R 0o} at the output terminal of the decoder. output for This operation is performed while the shutter 2 is open, and the proper exposure of the film is obtained, and the transistor is turned on by the operation of the shutter control circuit SC.
The process ends when TR ₁ is turned off and the shutter is closed. Therefore, if the number of pulse signals counted during this period is, for example, six as shown in FIG. 3, the output resistance of the decoder RDC is a resistance with a value corresponding to these six pulses, for example, _R is chosen as the setting resistance. On the other hand, when the transistor TR ₁ turns off, this off signal causes the differentiating circuit of the capacitor C ₃ and the resistor R ₂ to change the pulse width T ₂ (see Figure 3).
A trigger signal for activating the data imprinting circuit is created, which is applied to the monostable multivibrator through inverter IC ₈ to activate the same multivibrator. _The operating time T ₃ of this multivibrator is determined by the time constant of T ₃ = K ₃ (C ₄ R ₃ + C ₅ · R ₀₆ ), as shown in FIG. ,inverter
Transistor TR ₂ of the light emitting circuit from the output end of IC ₉
An operating voltage is applied to the base of the Therefore, current flows through the transistors TR ₂ and TR ₃ and the light emitter 11 only during the above-mentioned time T ₃ , the light emitter 11 emits light, and data is imprinted. Note that K ₃ above is a coefficient. Then, when the data imprinting is completed and the transistor TR ₂ is turned off and light emission stops, the reset circuit is activated by this off signal, and a reset pulse with a pulse width T ₄ shown in FIG. 3 is sent from the inverter IC _13. counter
is added to the EDC and the counter EDC is reset. The light emission time control circuit operates in this way.
What should be noted here is that the light emitting time of the light emitter 11 corresponds to the operating time _T3 of the monostable multivibrator, and this time T3 corresponds to the operating time _T3 of the monostable multivibrator.
It is controlled by the time constant of the output resistance R ₀₆ of the RDC and the capacitor C ₅ . This means that since the output resistor R ₀₆ is set according to the light transmittance of the film, the light emission time is always appropriate. Further, this light emission time _T3 does not change for the same film even if the subject brightness changes. That is,
If the subject brightness becomes brighter, for example, twice as much as in the case shown in Figure 3, the shutter speed will also be halved, and the transistor TR ₁ will become brighter, as shown in Figure 4.
The energization time is also halved, but since the light transmittance of the film is doubled, the resistance value of the photoelectric conversion element 9 that receives this transmitted light becomes smaller, and the pulse oscillator
The pulses generated by the OSC have a pulse width T ₅ which is _{T 1 /} 2 of the pulse width T 1 shown in FIG. 3, and the period is 1/2. Therefore, the number of pulses generated when the shutter is opened, in other words, the number of pulses counted by the counter EDC is 6, and the resulting light emission time _T3 is the same as that in Figure 3 above, so the data is not properly copied. be included. However, when the photographic film 2 is replaced and its light transmittance changes, the above light emission time T ₃
changes. That is, suppose that the thickness of the base of the replaced film becomes thicker, and the light transmittance drops to 1/2. If the subject brightness is the same as in the case of FIG. As shown in Figure 5, the pulse width in Figure 3
The pulse width T ₆ is twice that of the pulse T ₁ , and the period is also twice that of the pulse T 1 . Therefore, the number of pulses generated when the shutter is opened is 3, and the decoder
The output resistances R ₀₁ to _{R 0o} of the RDC are selected to have a large resistance value, for example, R ₀₃ . Therefore, the time constant C ₅ · R ₀₃ becomes large due to this, and the emission time T ₃ becomes longer than that shown in FIG. . Therefore, the data is properly printed without being underexposed. As described above, the data imprinting device of the present invention measures the light transmittance of the film, and thereby determines the light emission time _T3 of the light emitter 11, as shown by _T7 in FIG.
This is to ensure proper control. Therefore,
The amount of light emitted from the light emitter 11 is automatically controlled to be optimal. Further, even in the case of high-speed photography using a motor drive device, there is no flow of data imprinted images due to automatic winding of the film. In other words, in a general high-speed motor drive device, the time it takes for the motor drive to connect the electrical contact for film winding is:
Since it is 35 msec to 45 msec or more, the maximum light emission time of the light emitter 11 in the imaging device of the present invention is
By setting the time to 30 msec or less, it is possible to prevent the data image from flowing even during high-speed winding. Additionally, when detecting a light signal, brightness detection may not be able to detect the subject sufficiently depending on the brightness of the subject, and the specified trigger may not be activated. However, the present invention uses a light amount detection method. Even in dark subjects, the amount of light can be detected sufficiently without causing any problems. As described above, according to the present invention, color,
It is possible to provide a data imprinting device for a camera that can automatically and optimally control data imprinting regardless of black and white film and film sensitivity.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a data imprinting device for a camera showing an embodiment of the present invention, FIG. 2 is a diagram showing an example of an electric circuit of the data imprinting device of the invention, and FIG. The sequence time chart of the electric circuit shown in FIG. 2, and FIGS. 4 and 5 are diagrams each showing the pulse generation state of the pulse oscillator that is generated in response to the light transmitted through the film. 9...Photoelectric conversion element, 11...Light emitter for data projection, OSC...Variable pulse signal generator.

Claims (1)

[Scope of Claims] 1. A photoelectric conversion element that receives light transmitted through the film during photographic exposure; and a photoelectric conversion element that receives light transmitted through the film. a variable pulse signal oscillator that generates a counting pulse signal at a corresponding interval; a means for counting the pulse signal generated by the pulse signal oscillator and selecting a time constant element according to the number of counts; and the time constant element. 1. A data recording device for a camera, comprising: a data recording light emitter whose light emitting time is controlled by;