JP2001013644A - Film unit with lens and camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a more inexpensive film unit with lens constituted so that the deterioration of focusing caused by the change of temperature is reduced by constituting a photographing lens of plural lenses having an inorganic glass- made positive lens. SOLUTION: The photographing lens L is constituted of plural lenses having the inorganic glass-made positive lens. Preferably, it is constituted of one inorganic glass-made positive lens and one plastic lens, and at least one surface of the plastic lens is aspherical. Besides, the image forming surface of an object by the lens L is curved by making the concave surface thereof face the photographing lens side. Then, the condition of 70<f2/Fno<150 is satisfied. Provided that (f) is the focal distance of a whole lens system and Fno is an open F number. Besides, the plastic lens L1 and the inorganic glass-made lens L2 are arranged in turn from the object side so as to satisfy the condition of 0.5<f/f2<8. Provided that (f2) is the focal distance of the lens L2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens-equipped film unit and a camera, and more particularly, to a lens-equipped film unit having a fixed-focus type photographing lens, in which a film is built in at a manufacturing stage, and a lens unit. 135 film other than A or A
The present invention relates to a camera having a fixed focus type photographing lens such as a PS film.

[0002]

2. Description of the Related Art (Prior Art 1) A film unit with a built-in film in a manufacturing stage and a fixed-focus type lens unit is known as a photographing lens. -329
No. 741 is disclosed. Japanese Patent Application Laid-Open Nos. 8-201686 and 8-1 disclose a three-lens configuration in which one lens made of inorganic glass and two lenses made of plastic are used.
No. 60292 is disclosed.

(Prior art 2) In a film unit with a built-in film and a fixed focus lens as a photographic lens, a new film is refilled into a used film unit with a lens, and the quality is rechecked. Those that are reused are known. In particular, when a photographic lens has scratches, dust, or the like, a method of disassembling an external cover and replacing the photographic lens is performed.

(Prior art 3) In cameras other than the above-mentioned lens-equipped film unit, there is also known a technology of a fixed focus type as a taking lens and a similar lens configuration.

[0005]

However, as a (problem of the prior art 1), in a fixed-focus type photographing lens, if only a plastic lens is used, a focus change due to a temperature change is large, and especially when the F-number becomes small. It is strongly susceptible to focus deterioration at distant and close distances.
For example, in the case of a conventional single lens configuration using only plastic lenses or a two-lens configuration having a focal length of 30 mm, a back focus of approximately 0.3 mm becomes longer at a temperature rise of 30 ° C. In addition, a film unit with a lens is simple and has good portability, has many target subjects, and is easily affected by environmental temperature changes.

[0006] (Problems of the prior art 2) include, in addition to the problems of the prior art 1 described above, furthermore, at the time of re-use, the lens can be efficiently attached and detached against scratches and dirt on the taking lens. In addition, there is a problem that it is difficult to perform the processing with high accuracy.

[0007] As a (problem of the prior art 3), general cameras other than the film unit with the lens also
There is a problem similar to the problem of the prior art 1. A fixed focus camera is simple and portable, has many target subjects, and is susceptible to environmental temperature changes.

One object of the present invention is to provide a lens-fitted film unit with less focus deterioration due to a temperature change, and a further inexpensive lens-fitted film unit.

Another object of the present invention is to provide a lens-equipped film unit which is less degraded in focus with respect to a change in a use environment temperature and which is easy to reuse.

[0010] Another object of the present invention is to provide a camera in which the focus is hardly degraded with respect to a change in the use environment temperature.

[0011]

The above object can be achieved by any of the following means. (1) In a film unit with a lens having a built-in film in a manufacturing stage in advance and having at least a fixed focus photographing lens, the photographing lens is composed of a plurality of lenses having at least one inorganic glass positive lens. A film unit with a lens.

(2) The film unit with a lens according to (1), wherein the lens other than the inorganic glass positive lens is a plastic lens.

(3) In a film unit with a lens having a built-in film at a manufacturing stage in advance and having at least a fixed-focus photographing lens, the photographing lens is composed of one inorganic glass positive lens and one plastic lens. A film unit with a lens, comprising: a lens.

(4) The lens-fitted film unit according to (3), wherein at least one surface of the plastic lens is aspheric.

(5) The lens with the lens according to any one of (1) to (4), wherein the imaging surface of the object by the photographing lens is curved with the concave surface facing the photographing lens. Film unit.

(6) The film unit with a lens according to any one of (1) to (5), wherein the following condition is satisfied.

70 <f ² / F _no <150 Equation (1) where f: focal length of all lens systems F _no : open F number (7) Any one of (1) to (6) above, wherein a plastic lens and an inorganic glass lens are arranged in this order from the object side.
A film unit with a lens according to item.

(8) The lens-equipped film unit according to (7), wherein the following condition is satisfied.

0.5 <f / f ₂ <0.8 (2) where f is the focal length of the entire lens system, and f _{2 is} the focal length of the inorganic glass lens. (9) The lens-equipped film unit according to (7), wherein the following condition is satisfied.

0.5 <f / f ₂ <0.7 Formula [3] where f: focal length of all lens systems f ₂ : lens of inorganic glass Focal length (10) The imaging lens according to any one of (1) to (6), wherein the photographing lens is disposed in the order of an inorganic glass lens and a plastic lens from the object side. Film unit with lens.

(11) The lens-equipped film unit according to (10), wherein the following condition is satisfied.

0.6 <f / f ₁ <1.2 ·············································· [4] where f: focal length of all lens systems f ₁ : focal length of inorganic glass lens (12) In the film unit with a lens according to any one of (1) to (11), a first lens frame of a lens closest to the object side of the photographing lens and a second lens frame of another lens. Wherein the lens unit is independently held.

(13) The film unit with a lens according to (12), wherein the first lens frame can be attached to and detached from the object side independently of the second lens frame.

(14) A camera having at least a fixed focus photographing lens, wherein the photographing lens is constituted by one inorganic glass positive lens and one plastic lens. .

(15) The camera according to (14), wherein at least one surface of the plastic lens is aspheric.

(16) The camera according to (14) or (15), wherein the following condition is satisfied.

70 <f ² / F _no <150 Equation (1) where f: focal length of all lens systems F _no : open F number (17) The camera according to any one of (14) to (16), wherein a lens made of plastic and a lens made of inorganic glass are arranged in this order from the object side.

(18) The camera according to (17), wherein the following condition is satisfied.

0.5 <f / f ₂ <0.8 (2) where f is the focal length of the entire lens system, and f _{2 is} the focal length of the inorganic glass lens. (19) The camera according to (17), wherein the following condition is satisfied.

0.5 <f / f ₂ <0.7 (3) where f is the focal length of the entire lens system, and f _{2 is} the focal length of the inorganic glass lens. (20) The camera according to any one of (14) to (16), wherein the photographing lens is disposed in the order of a lens made of inorganic glass and a lens made of plastic from the object side.

(21) The camera according to (20), wherein the following condition is satisfied.

0.6 <f / f ₁ <1.2 (4) where f is the focal length of the entire lens system f _{1 is} the focal length of the inorganic glass lens The term “camera” as used herein means any camera that has a fixed-focus shooting lens and has no built-in film at the manufacturing stage, such as a lens shutter camera using a J135 film or an APS film. Say. In addition, the sensitivity of the film used may be plural,
The aperture may be fixed or variable.

Next, each item will be described.

According to the constitution described in the above (1), the photographing lens is constituted by a plurality of lenses having a fixed focus type and having at least one positive lens made of inorganic glass. Deterioration of focus is reduced. In particular,
As the F-number becomes smaller, the camera becomes less susceptible to focus deterioration at distant and close distances.

According to the configuration described in the above (2), when the taking lens is a fixed focus type and at least one lens other than the positive lens made of inorganic glass is a plastic lens, in addition to the effects described above, Costs are reduced and productivity is improved.

According to the configuration described in the above (3), the photographing lens is a fixed-focus type, and is composed of one inorganic glass positive lens and one plastic lens, so that a change in the operating environment temperature is obtained. In contrast, even when the F-number becomes small, the focus is hardly affected by the focus deterioration at a distant place or a close place. In addition, cost reduction can be achieved with a two-lens configuration.

According to the constitutions described in the above (4) and (15), at least one surface of the plastic lens is aspherical, so that even if the inorganic glass lens on the far side from the object is a spherical lens, it is aspherical. , Spherical aberration,
Coma can be corrected well and cost can be reduced.

According to the configuration described in the above (5), when the imaging surface of the object by the taking lens is curved with the concave surface facing the taking lens, a lens-fitted film unit having a lens with less astigmatism can be obtained. Can be.

According to the configurations described in (6) and (16), when conditional expression [1] is satisfied, the depth of focus is suitable as a lens-equipped film unit having a fixed-focus type photographing lens. If the upper limit of [1] is exceeded, the depth of focus becomes too shallow, which makes the lens unsuitable as a fixed focus lens. Conversely, when the value goes below the lower limit of the conditional expression [1], the depth of focus becomes unnecessarily large, and the balance with other optical specification values is lost.

According to the constitutions (7) and (17), if the taking lens is disposed in the order of a plastic lens and an inorganic glass lens from the object side, the plastic lens on the object side By replacing only the lens, the inorganic glass lens on the image side can be easily reused as it is, and the cost can be reduced.

According to the configurations described in the above (8) and (18), when conditional expression [2] is satisfied, the coma of the off-axis light beam is small, the astigmatism is small, and the meridional field curvature is small. Further, a focus change due to a temperature change is small. When the value exceeds the upper limit of conditional expression [2], the coma of the off-axis light beam increases, and the astigmatism increases. Further, the meridional field curvature increases. Conversely, when the value goes below the lower limit of the conditional expression [2], a focus change due to a temperature change becomes large.

According to the configurations described in the above (9) and (19), when the conditional expression [3] is satisfied, the above (8) and (18)
From the effects described above, the coma aberration of the off-axis light beam is small, the astigmatism is good, and the focus change due to the temperature change is improved.

According to the constitutions described in the above (10) and (20), the taking lens is made of an inorganic glass lens from the object side,
If the plastic lenses are arranged in this order, the lens surface is less likely to adhere to dust and dirt due to static electricity, and the lens surface is not easily damaged.

According to the constitutions (11) and (21), when conditional expression [4] is satisfied, the curvature is small, the spherical aberration is small, and the focus change due to the temperature change is small. When the lower limit of the conditional expression is exceeded, the focus change due to the temperature change becomes large. Conversely, if the upper limit of conditional expression [4] is exceeded,
Positive distortion increases and spherical aberration increases.

According to the construction described in the above (12), when the first lens frame of the lens closest to the object side of the taking lens and the second lens frame of the other lens are held independently, the film with lens When the unit is reused, attachment and detachment of each lens can be easily performed independently.

According to the configuration described in (13), if the first lens frame can be attached and detached from the object side independently of the second lens, when the film unit with the lens is reused, The replacement of the first lens becomes easy.

According to the configuration described in the above (14), if the taking lens is composed of one inorganic glass positive lens and one plastic lens, it is possible to focus on a change in the use environment temperature. Degradation is reduced.

[0048]

Next, a film unit with a lens according to an embodiment of the present invention will be described with reference to the drawings. FIG.
FIG. 2 is a perspective view of a film unit with a lens according to the embodiment of the present invention, and FIG. 2 is a cross-sectional view showing an internal structure of a main part of the fixed focus camera of FIG. In addition, each embodiment,
The symbols used in the examples are as follows.

F _no : open F number of the taking lens f: focal length of the taking lens ω: half angle of view r: radius of curvature of the refracting surface _d : interval between the refracting surfaces N _d : refractive index at d-line ν _d : d Abbe number f ₁ : focal length of first lens component f ₂ : focal length of second lens component (Embodiment 1) A film unit with a lens according to an embodiment will be described with reference to the drawings. FIG. 1 is an external perspective view of a film unit with a lens, and FIG. 2 is a cross-sectional view showing an internal configuration of a main part of the film unit with a lens.

In FIG. 1, a release button 1 is provided above the camera.
In front of the camera, there is a photographing lens L substantially at the center, and a finder 15 is provided thereon. In addition, a flash emission window 16 is provided at the upper right of the camera.

As shown in FIG. 2, the lens-fitted film unit is composed of a unit main body 10 in which each mechanism is incorporated, a front cover 11, a rear cover 12, and the like. A photographing screen frame 10c is provided substantially at the center of the unit body 10, and the photographing screen frame 10c is curved toward the photographing lens L. With the shooting screen frame 10c interposed, the spool S
Unexposed film chamber 10 containing a film wound around
a, an exposed film chamber 10b in which a patrone P for storing an exposed film is loaded on the other side.

A photographing lens L is provided substantially at the center of the unit body 10, and the photographing lens L is composed of a first lens L1 and a second lens L2. The second aperture A2 is a second lens L2
The first aperture A1 is provided between the first lens L1 and the second lens L2. The first stop A1 limits off-axis light flux, and the second stop A2 is an aperture stop. A shutter 17 is provided on the photographic screen frame 10c side of the photographic lens L. F indicates a film.

As the taking lens L, a taking lens described in an embodiment to be described later is used. The taking lens L is of a fixed focus type and is composed of one positive lens made of inorganic glass as a first lens L1 and one plastic lens made of a second lens L2. Lens and plastic lens in this order. One surface of the plastic lens is aspherical.

The focal length f of the photographing lens L and the open F number F satisfy the relationship of 70 <f ² / F _no <150, and the focal length f of the photographing lens L and the focal length f of the first lens are satisfied. ₁ of the relationship is to satisfy the relationship of _{0.6 <f / f 1 <1.2} .

The photographing lens L may be a plurality of lenses having at least one positive lens made of inorganic glass, and at least one lens other than the positive lens made of inorganic glass may be a plastic lens. . Further, the taking lens L may be arranged in the order of a plastic lens and an inorganic glass lens from the object side.
In this case, the relationship of 0.5 <f / f ₂ <0.8 is satisfied.

(Embodiment 2) Another film unit with a lens according to the embodiment will be described with reference to the drawings. FIG. 3 is a cross-sectional view showing an internal configuration of a main part of another film unit with a lens. The appearance of the film unit with a lens is the same as that of FIG. 1 described above.

As shown in FIG. 3, the lens-fitted film unit is composed of a unit body 10, a front cover 11, a rear cover 12, and the like in which the respective mechanisms are incorporated. A photographing screen frame 10c is provided substantially at the center of the unit body 10, and the photographing screen frame 10c is curved toward the photographing lens L. With the shooting screen frame 10c interposed, the spool S
Unexposed film chamber 10 containing a film wound around
a, an exposed film chamber 10b in which a patrone P for storing an exposed film is loaded on the other side. A photographic lens mechanism is incorporated in the unit body 10, and the photographic lens mechanism has a first lens L1 having a front inorganic glass material incorporated in a first lens frame H1 from the front side. Further, the second lens L2 having the rear plastic material is incorporated into the second lens frame H2 from the rear surface side. Therefore, the first lens frame H1 of the lens closest to the object side of the photographing lens L and the second lens frame H2 of the other lens are held independently.

When the film unit with a lens is reused, the first lens frame H1 can be attached and detached from the object side independently of the second lens frame H2.
If the lens L1 has a flaw or the like, the first lens L
Only one can be replaced. Therefore, there is an effect that dust and dirt hardly adhere to the second lens L2, and the step of cleaning the second lens L2 can be omitted.

(Embodiment 3) A camera according to an embodiment will be described with reference to the drawings. FIG. 4 is a cross-sectional view showing the internal configuration of the main part of the camera. The appearance of the camera is the same as that of FIG.

As shown in FIG. 4, the camera is composed of a unit body 10, a front cover 11, and a rear cover 12 in which the respective mechanisms are incorporated.
And so on. A photographing screen frame 10c is provided substantially at the center of the unit body 10, and the photographing screen frame 10c is curved toward the photographing lens L. On the other hand, an unexposed film chamber 10a having a patrone P with a built-in film on one side and an exposed film chamber 10b having a spool S for winding the exposed film are arranged on the other side of the photographing screen frame 10c. . A photographic lens L is incorporated in the unit body 10, and a photographic lens described in “Examples” described later is used as the photographic lens L. The taking lens L is of a fixed focus type, and one positive lens made of inorganic glass and one plastic lens are built in a lens frame H from the object side. At least one surface of the plastic lens is aspheric. Further, the taking lens L has a surface on which an image is formed is curved with a concave surface facing the taking lens.

The photographing lens L has a first aperture A1 and a second aperture A1.
It has an aperture A2, the first aperture A1 limits off-axis light flux, and the second aperture A2 is an aperture stop. Second
The aperture A2 is provided between the second lens L2 and the shutter 17, and the first aperture plate A1 is provided with the first lens L1 and the second lens L2.
It is installed between. Ratio of the focal length f and the open F-number F of the entire lens system satisfies the condition of _{^{70 <f 2 / F no <}} 150, further relationship of the focal length f ₁ of the focal length f and the first lens of the entire lens system The condition of 0.6 <f / f ₁ <1.2 is satisfied.

The photographing lens L may be a plurality of lenses having at least one positive lens made of inorganic glass.
At least one lens other than the positive lens made of inorganic glass may be a plastic lens. further,
The taking lens L may be arranged in the order of a plastic lens and an inorganic glass lens from the object side. In this case, the relationship of 0.5 <f / f ₂ <0.8 is satisfied.

[0063]

Embodiments of the present invention will be described below. The shape of the aspherical surface used in the present invention is expressed by the following equation (1), where the coordinate is the X axis in the optical axis direction and the height in the direction perpendicular to the optical axis is h.

[0064]

(Equation 1)

In Equation 1, K is the conic constant of the aspheric surface, A ₄ ,
A ₆ , A ₈ , A ₁₀ , and A ₁₂ indicate aspheric coefficients.

(Example 1) FIG. 5 is a sectional view of a lens, and FIG. 6 is a diagram of lens aberration. Tables 1 and 2 show lens data.

[0067]

[Table 1]

[0068]

[Table 2]

The first lens L1 is an acrylic plastic lens having one surface made aspheric. The second lens L2 is a lens made of inorganic glass and has a spherical surface on both sides, and can be used with an F number of F _no = 6.7 to 12.

In a conventional single-lens configuration having only a plastic lens or a two-lens configuration having a focal length of 30 mm, the back focus of about 0.3 mm becomes longer at a temperature rise of 30 ° C. Since the second lens L2 was made of an inorganic glass lens and had a sufficient refractive power, the back focus elongation could be suppressed to 0.177 mm even at a temperature rise of 30 ° C. Further, as can be seen from the lens aberration diagram of FIG.

(Example 2) FIG. 7 is a sectional view of a lens, and FIG. 8 is a diagram of lens aberration. Tables 3 and 4 show lens data.

[0072]

[Table 3]

[0073]

[Table 4]

The second embodiment is the same as the first embodiment except that the second lens L2 has a sufficient refractive power of an inorganic glass lens, so that the back focus elongation is 0.169 mm even at a temperature rise of 30 ° C. Could be held down. In addition, as can be seen from the lens aberration diagram of FIG. 8, each aberration is favorably performed.

(Embodiment 3) FIG. 9 is a sectional view of a lens, and FIG. 10 is a diagram of lens aberration. Table 5 shows the lens data.
It is shown in Table 6.

[0076]

[Table 5]

[0077]

[Table 6]

The first lens L1 is a lens made of inorganic glass and has a spherical surface on both sides, and the second lens L2 is an acrylic plastic lens and both surfaces are aspherical. The F number is available with F _no = 6.7 to 12.

Since the first lens L1 is made of inorganic glass and has a sufficient refractive power, the back focal length can be suppressed to 0.044 mm even at a temperature rise of 30 ° C. As can be seen from the lens aberration diagram of FIG. 10, each aberration is favorably performed.

Next, Table 7 shows the values of the conditional expressions in Examples 1 to 3.

[0081]

[Table 7]

As shown in Table 7, each condition satisfies each conditional expression.

[0083]

According to the configuration described above, the following effects can be obtained. A film unit with a lens that is less degraded in focus due to changes in the operating environment temperature, and an inexpensive film unit with a lens. In addition, the lens-equipped film unit can be easily reused, in addition to being less deteriorated in focus with respect to the change in the use environment temperature. In addition, a camera with less focus deterioration due to changes in the operating environment temperature.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a film unit with a lens.

FIG. 2 is a cross-sectional view showing an internal configuration of a main part of the film unit with a lens.

FIG. 3 is a cross-sectional view showing an internal configuration of a main part of another film unit with a lens.

FIG. 4 is a cross-sectional view showing an internal configuration of a main part of the camera.

FIG. 5 is a lens cross-sectional view of Example 1.

FIG. 6 is a lens aberration diagram of the first embodiment.

FIG. 7 is a sectional view of a lens according to a second embodiment.

FIG. 8 is a lens aberration diagram of the second embodiment.

FIG. 9 is a sectional view of a lens according to a third embodiment.

FIG. 10 is a lens aberration diagram of the third embodiment.

[Description of Signs] 10 Unit body 10c Photographing screen frame H1 First lens frame H2 Second lens frame F Film L Photographing lens L1 First lens L2 Second lens

Claims (21)

[Claims] 1. A film unit having a built-in film at a manufacturing stage and having at least a fixed-focus photographing lens, wherein the photographing lens includes a plurality of lenses having at least one positive lens made of inorganic glass. A film unit with a lens, characterized in that: 2. The lens-fitted film unit according to claim 1, wherein the lens other than the inorganic glass positive lens is a plastic lens. 3. A film unit having a built-in film at a manufacturing stage and having at least a fixed-focus photographing lens, wherein the photographing lens is composed of one positive lens made of inorganic glass and one plastic lens. A lens-equipped film unit comprising a lens. 4. The film unit with a lens according to claim 3, wherein at least one surface of the plastic lens is aspherical. 5. The film unit with a lens according to claim 1, wherein an image forming surface of the object by the photographing lens is curved with a concave surface facing the photographing lens. 6. The film unit with a lens according to claim 1, wherein the following condition is satisfied. _{^{70 <f 2 / F no <}} 150 where, f: focal length F _no total lens system: open F number 7. The photographing lens according to claim 1, wherein the photographing lens is disposed in the order of a plastic lens and an inorganic glass lens from the object side.
A film unit with a lens according to item. 8. The film unit with a lens according to claim 7, wherein the following condition is satisfied. 0.5 <f / f ₂ <0.8, where f: focal length of all lens systems f ₂ : focal length of inorganic glass lens 9. The lens-equipped film unit according to claim 7, wherein the following condition is satisfied. 0.5 <f / f ₂ <0.7, where f: focal length of all lens systems f ₂ : focal length of inorganic glass lens 10. The film with a lens according to claim 1, wherein the taking lens is disposed in the order of a lens made of inorganic glass and a lens made of plastic from the object side. unit. 11. The lens-equipped film unit according to claim 10, wherein the following condition is satisfied. 0.6 <f / f ₁ <1.2 where f: focal length of all lens systems f ₁ : focal length of inorganic glass lens 12. The film unit with a lens according to claim 1, wherein a first lens frame of a lens closest to the object side of the photographing lens and a second lens frame of another lens. A film unit with a lens, which is held independently. 13. The lens-equipped film unit according to claim 12, wherein the first lens frame can be attached and detached from the object side independently of the second lens frame. 14. A camera having at least a fixed-focus photographing lens, wherein the photographing lens is composed of one inorganic glass positive lens and one plastic lens. 15. The plastic lens according to claim 14, wherein at least one surface of the plastic lens is aspheric.
The camera according to. 16. The camera according to claim 14, wherein the following condition is satisfied. _{^{70 <f 2 / F no <}} 150 where, f: focal length F _no total lens system: open F number 17. The camera according to claim 14, wherein the taking lens is arranged in the order of a plastic lens and an inorganic glass lens from the object side. 18. The camera according to claim 17, wherein the following condition is satisfied. 0.5 <f / f ₂ <0.8, where f: focal length of all lens systems f ₂ : focal length of inorganic glass lens 19. The camera according to claim 17, wherein the following condition is satisfied. 0.5 <f / f ₂ <0.7, where f: focal length of all lens systems f ₂ : focal length of inorganic glass lens 20. The camera according to claim 14, wherein the taking lens is disposed in the order of a lens made of inorganic glass and a lens made of plastic from the object side. 21. The camera according to claim 20, wherein the following condition is satisfied. 0.6 <f / f ₁ <1.2 where f: focal length of all lens systems f ₁ : focal length of inorganic glass lens