JPS62191815A - Door scope device - Google Patents

Abstract

PURPOSE:To constitute the titled device so that a face of a visitor can be confirmed even from a position which is separated considerably in a room, by placing a uniaxial erect prism and a large-sized eyepiece, in the rear of a small- sized retrofocus type objective lens system. CONSTITUTION:What is called a uniaxial erect prism system consisting of a deformed triangle prism 2 and an isosceles triangle roof prism 3 is placed in the rear of a small-sized retrofocus type objective lens system 1. Also, in its rear, an eyepiece system consisting of a large-sized divergent lens system 4 and a convergent lens system 5 is pressed and fixed to a door 11 by an adhesive plate 9 and a detent 10. According to this constitution, an external inverted image of the objective lens system 1 is erected by the uniaxial erect prism, and magnified by the eyepiece system. Accordingly, the objective lens system 1 can be made small in size so as not to attractive to a visitor, and also, a face of the visitor can be confirmed even from a position which is separated considerably in a room.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a door scope device that is attached to a general door and is used to obtain information on visitors from inside the room.

(Prior art) Conventional door scope devices place too much emphasis on miniaturization and low cost, and many of their lens diameters are 10 mm or less.
They even tend to compete with each other in terms of the wide viewing angle, and for this reason, some objective lenses are considerably larger than the eyepieces, making them more noticeable to visitors, and their optical systems are generally constructed in the reverse Galilean type. It is wide-angle, which causes large negative distortion, and its exit pupil is small and close to the eyepiece, so it is generally crowded to obtain all the information within the wide viewing angle. Earthen floor (Ri\ki)
There are many objects that you have to touch with your eyes when you step into the room, and if you look at them from a distance and be careful not to touch your glasses, your wide field of view will be extremely narrowed, and your viewing angle will be even wider. Because of this, the information density was too high, making it difficult to quickly judge the faces of visitors, which was a major obstacle to practical application.

(Problems to be Solved by the Invention) This invention was made in order to eliminate the above drawbacks, and its optical system is extremely compact, and the iUj group is a divergent system and the rear group is a convergent system. It is a Keplerian type inverted telescope system with a short overall length, consisting of a type objective lens system, a large eyepiece system that magnifies the reduced external image, and a uniaxial erecting prism system in the middle. Distortion caused by the objective lens system is offset by the eyepiece system, limiting the viewing angle to a limit that allows the visitor's face to be quickly and clearly determined even from a considerable distance in the room, resulting in lower costs. The object of the present invention is to provide a door scope device with a sufficiently large exit pupil diameter and highly improved practicality, without necessarily placing the greatest emphasis on

(Means to solve the problem) The original mission of the door scope was that when a visitor presses the bell, the visitor can be quickly identified from within the room before the door is opened, and the visitor can be monitored. In order to prevent people from noticing as much as possible, and for general security reasons, the inside of the room cannot be seen from the outside through the door scope.Recently, on the contrary, they are installed in banks etc. in the style of ``A fierce dog:)''. There is a tendency to make it clear to visitors that security monitoring is being carried out, such as security cameras and intercoms with TV cameras, which have a positive effect apart from being expensive. , this invention was developed to fulfill its original mission. Therefore, in these days when door scopes have become popular, it is not necessarily a good idea to attach them to the door so that visitors do not notice.

In order to fulfill the original mission of the door scope, the objective lens (especially the first lens) that is visible to visitors must be made as small as possible.
It is easier to see the eyepiece if it is as large as possible, and this has the advantage of being able to greatly magnify the external image of the objective lens even from a considerable distance, but when this is attached to a door, the protrusion 1 from the inside of the door is If it is too large, it will get in the way in Japanese houses that often open outward, so it is necessary to limit it as much as possible. It is even more desirable to be able to clearly and quickly confirm not only the figure, but also the appearance of a person, and since the size of a human head can be considered to be approximately constant, it is necessary to meet this additional condition. , the average distance of the visitor from the door, the optimal monitoring distance from the inside of the door, and the amount of protrusion from the inside of the door when this device is installed, etc., the image reduction ratio, focal length, and viewing angle of the objective lens. Also, the effective diameter of the eyepiece, its power, etc. can be determined rationally.

There is a slight difference in the thickness of regular wooden doors and non-combustible metal doors, but most are around 36 mm thick, so the door thickness should be set at this value, and +15 mm (5 mm)
1mm thick) and -15mm (21mm thick), the average distance of visitors from the zero side of the door is approximately 80cm, and the optimal monitoring distance from the room is approximately 70cm (general house). The present invention will be described below with reference to embodiments, assuming that the amount of protrusion from the inside of the door when this device is attached to the door is approximately 4 cm or less.

Fig. 1 is a longitudinal cross-sectional view of the present invention, and ■ indicates the ignition distance in order to make the entire peeling device compact.

The effective diameter, overall length, etc. are all small, and in particular, the first lens diameter is made small, so the entrance pupil position is close to the first surface of the lens system, and the exit side is telecentric, so that the viewing angle is the same as indoors under the above conditions. The objective lens system is set to within the limit where the visitor's face can be clearly seen from the optimal monitoring position.
■ and ■ are respectively a deformed triangular prism and an isosceles triangular roof whose one end is provided close to the image plane of the objective lens system (■).
The prism is a so-called uniaxial erect prism system (hereinafter referred to as number 0) in which both are in contact with each other through an aperture plate.
(referred to as PECHAN PRISM), which has a long actual optical path length but a small shape in the optical axis direction, and immediately after that, a diverging lens system (■) and a convergent lens system (■) are placed, and these two are integrated. The external inverted image of the objective lens system ■ constitutes a convergent eyepiece system (hereinafter referred to as number 0) that provides erect magnified vision through a uniaxial erecting prism system (θ), and all these optical members is aligned on one axis and sealed inside the main body ■ in a way that maintains moisture and vibration resistance, and the strong adhesive tape ■ is placed so that the tip of the objective lens system ■ slightly protrudes from the outer surface of the door ■. It is affixed and fixed to the door (■) by pressing it with an adhesive plate (2) with a plurality of retainers (2), a retainer (2), and a rabbit.

Figure 2 is an optical path diagram of the uniaxial erecting prism system 0, whose optical path is A B CD E F G H, and its incident chief ray A
B and the exit chief ray GH coincide and are on the optical axis of the objective lens system (■), and the inverted image of the objective lens system (■) is made into a normal image by the five reflecting surfaces and one roof surface, and the effective diameter of incidence is The image height of the objective lens system ■ is equally small, but the eyepiece system @
Since we want to make the effective diameter as large as possible and keep the length of the entire system as short as possible, naturally the effective diameter of the injection becomes large, and therefore the shape of the uniaxial erecting prism system 0 becomes large.
Considering the compactness of the entire system of the fruiting device, it is most convenient to balance the shape of the uniaxial erecting prism system and the effective diameter of the eyepiece system, and make them approximately the same size as X'. In this case, it is possible to configure a convergent eyepiece system @ by arranging a diverging lens system ■ and combining it with a converging lens system ■. In the eyepiece system including the lens, it has become easy to correct residual aberrations of itself and the objective lens system, especially distortion, monochromatic aberration, etc.As a result, in the present invention, the uniaxial erecting The effective incident diameter of prism system 0 is 5 mm.
Even if the effective exit diameter is 25 mm and the entire system is limited as much as possible as described above, the effective diameter of the eyepiece system @ is 40 mm.
In this case, the shape of the uniaxial erecting prism system and the ocular lens system are the same, and in this case, the optical path of the uniaxial erecting prism system ( The length is 67.5935mm as ncA = 1.51633
The actual length in the optical axis direction is 25.500 mm.
That's short. Since the image plane of the objective lens system (■) and one end surface of the uniaxial erecting prism system (■) are close to each other, the image height of the objective lens system (■) is also considered to be Q5 mm. To examine other characteristics of the optical system of the system, in its explanatory diagram, Figure 3, ■ is the objective lens system, ■ is its image plane, @ is the eyepiece system, and ■ is the eyepiece system [phase]. The distance is 7
If θ is the half visual angle from the eye position for an eyepiece system @ with an effective diameter of 40 mm at the eye position 0 cm away, then θ=tan
' (20/700) = 1.6366゜Eyepiece system @
If the focal length of is fε, then rε=(5/2)÷tano
In this case, if the exit pupil diameter at the optimal indoor monitoring position (70 cm) is set to 40 mm and various aberrations of the eyepiece system @ are corrected, even if the eye is slightly off the optical axis, the outside world can be seen. It naturally becomes easier to find an optical axis that allows you to see part of the image and view the entire field of view.

Next, we prototyped three types of objective lens system (2) with an image height of 5 mm, with viewing angles of 160°, 120°, and 90°, and as a result of viewing from the optimal indoor monitoring position, we found that If the average position is 80 cm from the front of the door and the condition is that the visitor's face can be quickly and clearly determined, the viewing angle is 160°.

It was found that with a angle of 120°, it was impossible to judge the human face at all, and with an angle of 90°, that was the limit.

Approximately 40cm in size to the head including part of the human chest
When viewed from this position, the magnification of the eyepiece system @ can be considered as 40 mm ÷ 5 mm = 8 X, so
The relationship between the height of the enlarged image and the average position of the visitor is shown in the table above, which shows that the rough pattern within a square area of 13.6 mm can be resolved from a distance of 70 cm.

Of course, this experiment was conducted using a person with slightly poor eyesight, and the position of the visitor and the visual acuity of the observer were not constant, so it is not absolute, but the above conditions to confirm this device. is not completely meaningless. It goes without saying that the numerical values in the above table were calculated after determining the focal length of the objective lens system (2) described below.

Since the exit side of the retrofocus objective lens system (■) with a viewing angle of 90° is telecentric, it naturally generates a large negative distortion, but if this is zero, then when the focal length of the objective lens system (■) is fo. fo=2,5/
jan45° = 2.5 mm, but since the distortion of the eyepiece lens system @ is about -30%, in order to offset this, the same degree of distortion is left in the objective lens system ■, and ro = 3.42 mm. When , the image height is 5 mm1 and the total length is 15.75 mm.
When this device was attached to a door with a standard thickness of 36 mm, the amount of protrusion of the device from the inside of the door was only 33.03 mm.

Now, the viewing angle of 90° is much narrower than that of conventional products, but many houses have shrubs on both sides of the entrance door, and visitors are generally placed a little further away within 90° in front of the door. Since people often stand up, this can serve a certain purpose, and as mentioned above, rather than competing for an ultra-wide field of view that has many disadvantages in monitoring, it is possible to quickly and clearly see the number of visitors at the optimal indoor monitoring position. In practical terms, being able to determine the phase is closer to the original purpose of the door scope.

(Effects of the Invention) As detailed above, according to the present invention, when attached to a general door, the objective lens system that is noticeable to visitors is small, the eyepiece system is large, and the exit pupil of the entire system is large and far away. Therefore, even from a considerable distance in a room, it is easy to see and even the facial features of visitors can be determined.It is a single-axis compact system, the entire system is short, and a normal image without distortion can be obtained. It has a great effect in adapting to doors with a certain thickness.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an embodiment according to the present invention, FIG. 2 is an optical path diagram of a uniaxial erecting prism (Pechan prism) applied to FIG. 1, and FIG. 3 is an optical path diagram of an embodiment of the present invention. FIG. 3 is an explanatory diagram of system characteristics. ■...Objective lens system ■...Deformed triangular prism■
...Isosceles triangular roof prism ■...Divergent lens system ■...Convergent lens system ■・
・・Body ■・・・Strong adhesive tape■・・・
Set screw ■...Joint board [Co., Ltd.]...Latch ■...Door ■...Single-axis erecting prism (Pechan prism) @...Eyepiece system E...Eye Position F...focal plane of objective lens system Patent applicant Representative Director of Natural Science Institute Co., Ltd.
Masao Komatsu

Claims (6)

[Claims] (1) A uniaxial erecting prism system and a large eyepiece lens system are placed behind a compact retrofocus objective lens system with a short focal length, so that a large external image can be confirmed even from a considerable distance. All of these optical components are arranged on one axis, and sealed inside the main body to maintain moisture resistance and vibration resistance.This is affixed with strong adhesive tape, and multiple setscrews are attached. A door scope device characterized in that it is crimped and fixed to a door using an adhesive plate having the following properties and a stopper. (2) The door scope device according to claim 1, further comprising an objective lens system having an entrance pupil position located near the first surface of the lens system. (3) A door scope device according to claims 1 and 2, characterized in that an objective lens system whose exit side is telecentric is provided. (4) Claim 1, characterized in that an objective lens system is arranged whose viewing angle is limited to a limit that allows the visitor's facial features to be clearly seen even from a considerable distance;
The door scope device described in paragraphs 2 and 3. (5) A uniaxial erect prism system (Pechan/
Claims 1 and 2, characterized in that a prism) is disposed between the objective lens system and the eyepiece system.
The door scope device according to paragraphs 3 and 4. (6) A convergent eyepiece system is constructed by combining a diverging lens system and a convergent lens system, and this is arranged behind the objective lens system and the uniaxial erecting prism system. The door scope device according to paragraphs 1, 2, 3, 4 and 5.