JPS6151538B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an optical projection device, and particularly to a method for manufacturing a compound eye lens device that is a component of a projection device that forms a mirror image of an object on a projection surface. A projection device that forms a mirror image of an object on a projection surface is
It is particularly used in copying machines that have a transfer process. Incidentally, a conventional projection device in a copying machine or the like uses a monocular lens system, that is, a projection lens system having only one optical axis. However, since the optical conjugate distance of a monocular lens system is relatively long, it has been difficult to miniaturize a copying apparatus using a monocular lens system as a projection lens system. As a result, efforts have been made to shorten the conjugate distance of the projection lens system in order to downsize copying machines, and as a result, one solution has been to replace the projection lens system with multiple lens systems with relatively short conjugate distances. Projection devices have been proposed with compound eye lens systems arranged in a direction perpendicular to the axis. In this projection device, each elemental lens system (lens system arranged along the optical axis extending between the object and the projection surface) constituting the compound eye lens system produces an image of each part of the object to be projected on the projection surface. The entire compound eye lens system forms a projected image of the entire object on the projection plane. For example, in Patent Application Publication No. 8893 published on February 28, 1971, a belt-shaped area of a document to be copied is covered with a plurality of element lens systems arranged along the longitudinal direction of this belt-shaped area. , a projection apparatus is shown in which each partial image of a band-shaped area is formed on a photoreceptor by these elemental lens systems. Each elemental lens system of this projection device is composed of three lenses, namely, a front lens, an intermediate lens, and a rear lens. It is formed on the intermediate lens arranged. The intermediate image formed on the intermediate lens is then re-imaged as a mirror image on the photosensitive material by the rear lens. This intermediate lens performs a field lens function and has no relation to the original projection function. However, this field lens is an important lens from the viewpoint of maintaining uniform brightness of the projected image formed on the photosensitive material. In response to such a projection optical system, the present applicant has disclosed a projection optical system in JP-A-53-122426, which reduces the number of lenses constituting the element lens system without reducing the brightness of the projected image. Although,
The present invention also provides a new and improved projection apparatus that also includes a newly proposed projection optical system. Therefore, first, the projection optical system used in the present invention will be explained. Three types of projection optical systems are listed as examples for this purpose. These projection optical systems use a compound eye optical system in which each elemental lens system consists of two lenses or substantially two lenses, and an overview thereof is shown in FIGS. 1a and 1b. Here, FIG. 1b shows a reflective compound eye optical system, 5 is a half mirror, and 6 is a compound eye lens 7 which is a mirror. The two lenses constituting each element lens system in FIG. 1a are a first lens 1 which is substantially telecentric on the image field side and a second lens 2 which is substantially telecentric on the object side. Here, the term "substantially telecentric lens" means a lens that provides an exit or input chief ray that is parallel or nearly parallel to the optical axis. Then, the image field side surface of the first lens and the object world side surface of the second lens have a field lens function, thereby maintaining the brightness of the projected image.
A projection optical system having a smaller number of lenses than the projection optical system disclosed in Japanese Patent Publication No. 79-8893 mentioned above can be obtained. Furthermore, since each lens is substantially telecentric, the action of the substantial field lens formed by the image field side surface of the first lens and the object field side surface of the second lens exhibits maximum efficiency. Therefore, the projected image can be effectively brightened. This lens is essentially telecentric, and compared to its effective diameter,
The length along the optical axis is large. Therefore, this type of lens will hereinafter be referred to as a bar lens. In Fig. 1a, each element lens forms an image of each part of the document D once between two bar lenses, and then re-forms it on the projection plane P, and then the document is captured by two rows of compound eye systems. An image 4 of the band-like portion 3 of D is formed, and the image 4 of the belt-shaped portion 3 of
The entire image of the document surface is sequentially formed on the projection surface by moving the document surface relatively in a direction perpendicular to the above-mentioned band-shaped portion 3. Further, in FIG. 1b, an intermediate image of the document D is formed on the mirror 7, and is again formed on the projection plane P. An example will be described below. Example 1 This is explained in detail in the above-mentioned Japanese Patent Application Laid-Open No. 53-122426. Figure 2 is for explaining the action of one element lens system.
0 is an object, that is, a part of the original. 11 is an aperture stop placed at the entrance pupil of the bar lens 21; 12
is a field stop disposed on the surface where the intermediate image 13 of the object 10 formed by the first bar lens 21 is formed. This field diaphragm serves to define the coverage area of the object plane. It is better to keep this field stop 12 as far away as possible from the image field side surface of the bar lens 21 and the object world side surface of the bar lens 22 to prevent images of dust attached to these surfaces from being formed on the projection plane. preferred. In order to include this field stop 12, it is preferable that the intermediate image be reduced in size. 15 indicates a chief ray. As mentioned above, the lenses 21 and 22 in FIG. The incident chief ray is parallel to the optical axis. Therefore, the light that has formed the intermediate image is efficiently re-imaged onto the projection plane by the lens 22 without loss of light quantity. That is, by making the lenses 21 and 22 telecentric lenses, the lens 2
The image field side surface of lens 1 and the object world side surface of lens 22 act as if they form an air lens, and substantially serve as a field lens. In this way, the present projection optical system does not require a field lens, and the number of lenses can be reduced. According to experiments conducted by the present inventors, the bar lenses 21 and 22 are the same lens (however, they are plane symmetrical with respect to the intermediate image 13), and the optical axis is set relative to the effective diameter of the lens. The lens thickness along the
It has been found that good results can be obtained by increasing the magnification by 60 times. In addition, as will be described later, the design of these lenses 21 and 22 is based on formulas 6 to 10 for the first lens 21.
It is desired that the lens 22 satisfy Equations 16 to 20. I will discuss the following. First, the first lens 21 will be explained. 1st
In order to simplify the explanation of the lens, the symbols given in FIG. 3 will be used. In the figure, _the radius of curvature r 1 of the first surface of the first lens 21, that is, the surface on the object side, the radius of curvature r ₂ of the second surface, that is, the surface on the image field side (negative amount in the figure), and the center of the first lens. The lens thickness, that is, the thickness of the first and second surfaces along the optical axis, is expressed as d ₁ ', and the principal refractive index of the material of this lens, that is, the refractive index for a typical design wavelength, is expressed as n ₁ '. do. Also, the effective diameter of this lens is represented by φ ₁ , the size of the object 10 is φ ₀ , and this lens 2
1, the size of the intermediate image 13 formed by φ ₂
The distance from the first surface of this lens 21 to the object 10 is expressed as S ₁ (negative amount in the figure), and the distance from the second surface of the first lens 21 to the intermediate image 13 is expressed as S ₂ '. Furthermore, the lateral magnification of the intermediate image 13 with respect to the object 10 is expressed as β ₁ (≡−|φ ₂ /φ ₀ |). The object-side effective F number of this lens 21 will be expressed as Fe. Effective F-number determined from lighting conditions, i.e. and the lateral magnification β ₁ (|β ₁ |<1) of the intermediate image, which is set so that there is no vignetting of the partial image, and the object distance S ₁
and the lens back S ₂ ' to the intermediate image are amounts that can be set in advance. Further, the principal refractive index n ₁ ' of the material is determined by setting the material. From these five setting amounts Fe, β ₁ , S ₁ , S ₂ ′, n ₁ ′, the radius of curvature r ₁ of the first surface of the first lens 21, the radius of curvature r ₂ of the second surface, and the center of the first lens The thickness d ₁ ', the effective diameter φ ₁ of the first lens, and the effective partial diameter φ ₀ of the object are determined from the following conditions using ideal imaging theory. First, the relationship between the magnification β ₁ and the lens configuration data is given by the following equation. β ₁ = 1/{ ₁ + ₂ − ₁ e ₁ ' ₂ }S ₁ + {1-e ₁
′ ₂ }……(2) Here ₁ ≡n ₁ ′-1/r ₁ (Refractive power of the first surface) ₂ ≡1-n ₁ ′/r ₂ (Refractive power of the second surface) e ₁ ′≡ d ₁ ′/n ₁ ′ Next, the condition that the chief ray of the incident light flux from the object, that is, the ray passing through the center of the first surface, exits parallel to the optical axis after exiting the second surface is exactly the same as the second Since this is equivalent to the fact that the focal length (ie _1/2 ) is equal to e ₁ ', it is expressed by the following relationship. _1/2 = e ₁ '...(3) Next, as a condition for the light beam entering the lens 21 from the end of the effective object diameter φ ₀ to not be eclipsed (second
(see figure), since the lower ray of light passes along the edge of the lens 21 parallel to the optical axis after passing through the first surface, the following relational expression can be obtained. ₁ = -1/S ₁ {1+φ ₀ /φ ₁ } ...(4) Finally, from the conditions for keeping the distance S ₂ ' from the second surface of the first lens 21 to the intermediate image position at an appropriate value in advance The following relational expression is required. S ₂ ′=β ₁ × {(1− ₁ e ₁ ′)S ₁ −e ₁ ′} ...(5) The conditions of equations (1) to (5) above are expressed as r ₁ , r ₂ ; d ₁ ′, φ ₁ ; φ ₀
By solving simultaneously, we uniquely obtain the following result. r ₂ = (1−n ₁ ′)×β ₁ S ₁ ……(7) d ₁ ′=n ₁ ′×β ₁ S ₁ ……(8) Next, the second lens 22 will be explained. As before, use the symbols given in Figure 3. In the figure, the radius of curvature of the first surface of the second lens 22, that is, the surface on the object side is r ₃ , and the radius of curvature of the second surface, that is, the surface on the image field side is r ₄ (negative quantity in the figure). The center thickness of the second lens, that is, the lens thickness between the first and second surfaces along the optical axis, is expressed as d ₂ ', and the principal refractive index of the material of this lens, that is, the refraction for a typical design wavelength. Let the rate be n ₂ ′. Also, the effective diameter of this lens is represented by _φ3 , the size of the projected image with respect to the second lens on the projection plane is represented by _φ4 , and the distance from the first surface of this lens 22 to the intermediate image 53 is represented by S. ₃ (negative amount in the figure), and the distance from the second surface of the second lens 22 to the projected image is expressed as S ₄ '. Furthermore, the lateral magnification of the projected image 14 with respect to the intermediate image 13 is β ₂ (≡
−|φ ₄ /φ ₂ |). The effective F number on the image field side of this lens 22 is expressed as Fe'. The effective F number determined from the conditions regarding the brightness of the projected image, that is, In order to avoid vignetting of the partial images, the lateral magnification β ₂ (|β ₂ |>1) of the projected image, the intermediate image distance S ₄ and the lens back S ₄ ' to the projection plane can be set in advance. Also, the principal refractive index of the material
n ₂ ′ is determined by setting the material.
From these set amounts Fe′, β ₂ , S ₃ , S ₄ ′, n ₂ ′, the radius of curvature r ₃ of the first surface of the second lens 22, the radius of curvature r ₄ of the second surface, and the lens center of the second lens The thickness d ₂ ', the effective diameter φ ₃ of the second lens, and the effective diameter φ ₄ of the projected image are determined by the following conditions using ideal imaging theory. First, the relational expression between the lateral magnification β ₂ and the configuration data of the lens 22 is given by the following equation. 1/β ₂ = 1/{ ₃ + ₄ - ₃ e' _{2 4} } (-S ₄ ') + {1-e ₂ ' ₃ } ...(12) Here ₃ ≡n ₂ '-1/r ₃ (Refractive power of the first surface) ₄ ≡1-n ₂ ′/r ₄ (Refractive power of the second surface) e ₂ ′≡d ₂ ′/n ₂ ′ Next, the incidence with the chief ray parallel to the optical axis In order for the light beam to pass through the second lens in an amount equal to or less than the effective diameter _φ3 of the second lens, it is desirable that the second surface of the second lens has an exit pupil. This request corresponds to the focal length of the first surface (i.e. 1/
₃ ) is equal to e ₂ ', we obtain the following relationship. _1/3 = e ₂ '...(13) Next, from the end of the effective intermediate image diameter φ ₂ , the second lens 2
As a condition for the light beam incident on the lens 22 to not be eclipsed (see Figure 2), since the rays at the bottom of the light beam pass through the first surface and follow the edge of the lens 22 parallel to the optical axis, the following relationship is established. The formula is obtained. ₄ = 1/S ₄ ′ {1+φ ₄ /φ ₃ }...(14) Finally, from the conditions for keeping the distance S ₃ from the first surface of the second lens 22 to the intermediate image position at an appropriate value in advance, the following A relational expression is required. S ₃ = 1/β ₂ × {1− ₄ e ₂ ′) S ₄ ′ + e ₂ ′ ……(15) The conditional expressions of equations (11) to (15) above are expressed as r ₃ , r ₄ , d ₂ ′, _φ3 ,
By solving simultaneously for φ ₄ , we uniquely obtain the following result. r ₃ = (1-n ₂ ′)×S ₄ ′/β ₂ ……(16) d ₂ ′=−n ₂ ′×S ₄ ′/β ₂ ……(18) φ ₄ = [S ₃ β ₂ − S ₄ ′/S ₄ ′/β ₂ ]×φ ₃ ...
...(20) Therefore, in the coaxial optical system combining the first lens 21 and the second lens 22, first, the intermediate image (image diameter size φ ₂ ) of the object to be projected (object diameter φ ₀ ) is formed by the first lens. is formed, and subsequently this intermediate image is relayed by the second lens onto the projection image plane as an erect image with a projection image diameter of ₄ without loss of uniformity of brightness. At that time, in order to consistently form the entire image of the object plane on the projection plane by arranging a plurality of coaxial optical systems each consisting of a first lens and a second lens, generally β ₁ ×β ₂
=+1, that is, it must be used with the same size erect. That is, it is necessary to consider the configuration of the first lens and the second lens so that the relationship β ₂ =1/β ₁ (21) is satisfied. And with such considerations, Fe'=Fe...(21) is obvious. In the end, in an erect equal-magnification coaxial optical system that combines the first lens 21 and the second lens 22, the first lens 21
If β ₁ and Fe are set under appropriate conditions, then β ₂ and Fe' of the second lens are naturally determined by equations (21) and (21'). However, the other setting values of the first lens, S ₁ , S ₂ ′, n ₁ ′, and the setting values of the second lens, S ₃ , S ₄ ′, n ₂ ′, are determined independently from each other under appropriate conditions. It must be noted that it is permissible to specify. Generally, it is desirable to avoid the difference in the configurations of the first lens and the second lens from a manufacturing standpoint by making two types of lenses. From this point of view, the above-mentioned first lens and second lens
Conditional expression for an erect equal-magnification coaxial optical system combining lenses
As the second lens satisfying (21) and (21'), a coaxial optical system in which the first lens is arranged symmetrically with respect to the intermediate image can be considered. Therefore, based on this idea, it becomes possible to use the first lens as the second lens. In this case, the specifications constituting the second lens are obtained from the following relationship with the specifications constituting the first lens. That is, r ₃ = −r ₂ , r ₄ = −r ₁ , d' ₂ = d' ₁ , n' ₂ = n' ₁ , φ ₃
= φ, φ ₄ = φ ₀ , β ₂ = 1/β ₁ , S ₃ =-
S′ ₂ , S′ ₄ =−S ₁ , F′e=Fe. Here, the following table lists design values for Examples 1 to 10 in which the first lens and the second lens are arranged symmetrically with respect to the intermediate image plane.

【table】

[Table] The configurations of compound lenses and masks using such elemental lens systems are shown in FIGS. 4 to 6. FIG. 4 is a view of the compound eye lens viewed from the optical axis direction, and is arranged in two rows in parallel. Pitch a is an appropriately selected value, and b is an arbitrary amount. As shown in FIG. 5, the field stop is arranged at the same pitch as the element lens system and is formed by the apertures 26 on the mask 25, and is located at position 12 in FIG.
As shown in FIG. 3, in the elemental lens system, the intermediate image is a reduced image, so the aperture 26 located on the same plane as the intermediate image is enlarged and projected onto the projection plane. This state is shown in FIG. 6a. Adjacent aperture images partially overlap each other in the direction perpendicular to the scanning direction indicated by the arrow, and the projection device is positioned relative to the document in the scanning direction. Gives uniform illumination to the projection surface when moving. The images of the apertures 26 of the mask 25 have hexagonal apertures as shown in FIG. 6b, and are arranged at appropriate intervals, so that the amount of light integrated in the scanning direction is constant in the arrangement direction. Note that due to this field stop, the light intensity distribution on the projection plane becomes a rectangular distribution as shown in FIG. 6C. Embodiment 2 The projection optical system of Embodiment 1 is characterized in that the light intensity distribution on the final image plane corresponding to the effective object field is almost flat. That is, for example, by providing a field diaphragm in the intermediate image screen section, in other words, by providing a diaphragm independent of the lens, the light intensity distribution on the final image plane is made substantially flat. On the other hand, in Example 2, without providing a field stop in the intermediate image plane, the lens barrel that connects the two lenses is used not as a mere holder but as a stop extending in the optical axis direction.
It is characterized by a unique optical system in which the light intensity distribution at the final image plane is flat (ie, zero vignetting) in a finite central region, and gradually increases in vignetting in the peripheral region. That is, in the second embodiment, the inner diameter surface of the lens barrel extending in the optical axis direction is positioned as a factor that influences the light intensity distribution on the projection plane, and is characterized by this. Furthermore, it is disclosed that optical performance can be improved by providing a permissible range for specifications such as the radius of curvature, and by arranging them in two staggered rows to increase flatness and to provide stable antireflection. FIG. 7 shows a cross-sectional view of the element lens system in the optical axis direction in Example 2. Here, the outer diameters of the inner diameter lenses 40 and 41 of the lens barrel 101 are the same, and the inner surfaces thereof are anti-reflective. Also, Figure 8a,
FIG. 8b explains the structure and function of the lenses 40 and 41. In this figure, 50 is an object, that is, a part of the document. Reference numeral 54 indicates a principal ray (a ray incident on the center of the first surface). As mentioned above, the lenses 40 and 41 are telecentric on the image field side in the lens 40 and telecentric on the object world side in the lens 41, so that the light exits the lens 40 or enters the lens 41. The chief ray is parallel to the optical axis. Therefore, the light that has formed the intermediate image is efficiently re-imaged onto the projection plane by the lens 41 without loss of light quantity. That is, by making the lenses 40 and 41 telecentric lenses, the lens 40
The image field side surface of the lens 41 and the object world side surface of the lens 41 act as if they form an air lens (a concave lens whose internal refractive index is smaller than the external refractive index is equivalent to a normal convex lens). Also functions as a field lens. However, it should be noted here that the image area where the image is re-imaged on the projection plane without loss of light quantity is within the finite area φ ₀ at the center. That is, it is within the area _φ2 on the intermediate image plane. Now, when the inner diameter of the lens barrel 101 is φ ₂₁ , φ on the intermediate image plane
The light flux from the object area exceeding ₂ and being imaged within the φ ₂₁ region, that is, the area corresponding to φ ₀ to φ ₀₁ on the object surface, is transmitted to the inner surface of the lens barrel of the lens 40, that is, the outer diameter surface of the lens, and the intermediate portion between the two lenses. The inner surface of the hole is chipped, causing caliber erosion. The degree of vignetting increases from φ ₀ to φ ₀₁ , and at φ ₀₁ the vignetting becomes 100%, that is, the light flux normally transmitted into the projection plane becomes zero. FIG. 9 shows a cross-sectional view of the light intensity distribution on the projection plane in such a case. The vertical axis is the light intensity, and the horizontal axis is the image height (angle of view). Here, φ ₄ and φ ₄₁ are φ ₀ and φ ₀₁ on the object plane, respectively.
corresponds to the conjugate on the projection plane. When optical systems that can provide such a light intensity distribution on the projection plane are arranged in a single row array at regular intervals, the distribution in the array direction of the light amount integrated in the direction perpendicular to the array direction is a sine. It becomes like this. Although a sinusoidal light intensity distribution may be acceptable (the array includes not only one row but a plurality of rows), the first lens 40 and the second lens 41 arranged coaxially as shown in FIG. The element lens systems configured by are arranged in two rows in a staggered manner (where the interval or pitch between each projection optical system is a, the second row is shifted by a half pitch, or a/2, from the first row). Then, the distribution of the amount of projected image light integrated in the direction perpendicular to the arrangement direction becomes approximately flat. Here, the staggered two-row arrangement may be used as one set, and there may be more arrangements. Note that the distance l between the first column and the second column is an arbitrary amount. The flatness described above can be obtained within several percent when the relationship between the pitch a and the effective object field of view φ ₀₁ satisfies the following conditions. K ₁ /2 x φ ₀₁ aK ₂ /2 x φ ₀₁ (K ₁ = 0.9, K ₂ = 1.1) In this way, this embodiment makes the light intensity of the projected image uniform and reduces the light intensity of the lens in the optical axis direction. The optical system has only two pieces, making it easy to adjust. That is, since the number of lenses is two, the relative relationship in the optical axis direction and in the direction perpendicular to the optical axis only needs to be adjusted once. By the way, according to experiments conducted by the present inventors, when the lenses 40 and 41 are the same lens (however, they are plane symmetrical with respect to the intermediate image 53), the length of the lenses along the optical axis is smaller than the effective diameter of the lenses. It has been found that good results can be obtained by increasing the magnification by a factor of 2 to 60. Moreover, the design of these lenses 40 and 41 is as in Example 1.
Similarly, for the first lens 40, formulas (6) to (10) second
It is desirable that the lens 40 satisfy equations (16) to (20). By the way, in Embodiment 2, the basic idea is to use the inner diameter surface of the lens barrel as a diaphragm extending in the optical axis direction, but the illuminance on the projection plane is _constant . Since the light reflected from the inner diameter surface of the lens barrel becomes stray light and adversely affects the light intensity distribution on the image plane, it is necessary to take sufficient anti-reflection measures. Inking the outer diameter surface of the lens, as is usually done here, is less favorable than the following points. That is, in the second embodiment, the lens is fitted into the lens barrel in order to accurately control the lens outer diameter and lens barrel inner diameter, which may cause peeling or the like during insertion. That is, in Embodiment 2, the inner diameter surface of the lens barrel not only has the function of simply preventing reflection and holding the lens, but also functions as a diaphragm that regulates the effective object field, and has a fairly long range in the optical axis direction, so a stable anti-reflection measure is desired. It is for this purpose. Therefore, as a stable anti-reflection measure,
As shown in Fig. 1a, a substance 62, which has almost the same refractive index as the lens and is equivalent to a lens barrel and attenuates the amount of incident light, is placed between the outer diameter surface of the lens and the inner diameter surface of the lens barrel.
It is also conceivable to insert a substance 63 that provides the same effect as 62 into the intermediate portion of the two lenses.
For example, a black plastic cladding material can be used as the light absorbing material for a lens made of transparent plastic material. This function will be explained with reference to FIG. 11b. A light ray 64 incident on the first surface of the lens on the object side from a field other than the object field φ ₀ where the illuminance on the projection plane is constant reaches the boundary between the cladding material and the lens. Since the lens and the cladding material have almost the same refractive index, the light reflected at this boundary 6
5 is not present, and almost all of it passes through and enters the cladding material.
The cladding material is a material that attenuates incident light by absorption and diffusion, and light 66 that passes through the cladding material, is further reflected at the boundary, and enters the lens again, and light 67 that passes from the cladding material toward the lens barrel side.
disappears. Here, the inner diameter of the clad material is _φ21 . Furthermore, as shown in FIG. 11c, the light ray 68 that passes through the second surface of the object-side lens and then enters the inner surface of the lens barrel needs to be attenuated as well. However, the intermediate part between the object side lens and the image side lens is an air layer, and if the above-mentioned crad material 62 that fits on the outer diameter of the lens is similarly used, there will be reflected light 69 due to the difference in refractive index. There is a problem that the cladding material increases, and it is necessary to use another light absorbing material 63 whose refractive index is close to that of air, unlike the cladding material. This results in unnecessary rays 69, 70, 7
1 is removed. Again, the inner diameter of the light absorbing cladding material is required to be equal to the outer diameter of the lens.
That is, _φ21 corresponding to _φ01 is required. With these, only the effective light beam can be transmitted and a light intensity distribution desired in terms of design can be created. Additionally, the clad material, which is the light absorption layer, also has the effect of blocking stray light from the outside. By the way, acrylic resin, plastics such as styrene, glass, etc. can be used as the transparent core material, and colored plastics, paints, etc. can also be used as the material of the light absorption layer. By the way, the above description has been made assuming that the lens effective diameter and the lens outer diameter are equal, but for example, as shown in FIG. 12, the lens 73
Even if the outer diameter φ ₂₁ is different from the effective diameter φ ₂₁ , it does not matter as long as the effective diameter and the outer diameter are substantially equal. However, the first
As shown in FIG. 2, it is necessary to make the portion 72 of the first and second surfaces other than the effective diameter a rough surface or a light absorption surface to prevent light from entering the lens. As described above, the second embodiment uses the lens effective diameter, that is, the lens outer shape as the basis for the light intensity distribution on the projection surface, and provides stable reflection prevention, thereby providing a compact projection device with good image performance.
Furthermore, the present inventor has determined that in Examples 1 and 2, the first lens and the second lens meet the conditional expressions (6) to (10), (16) to
About ±10% from (20), that is, We have actually designed and confirmed that it is acceptable to have a value as expressed by . Embodiment 3 In Embodiment 2, a projection optical system that does not require a field diaphragm was shown, but on the other hand, in order to project with uniform brightness as a whole when scanning the document surface, each elemental lens system must be equipped with at least two lenses. A staggered arrangement of rows was desirable. Embodiment 3 shows an optical system that does not require a field stop and is capable of projecting uniform brightness over the entire document even with a single row of compound eye systems. In Embodiment 3, when optical systems capable of providing a Gaussian light intensity distribution on the projection plane are arranged parallel to each other in one or more rows at equal intervals, the effective object field of each component lens system overlaps in multiple directions. , represents an optical system in which the distribution in the array direction regarding the amount of light integrated in the direction perpendicular to the array direction is approximately flat. In Embodiment 3, the effective object field of view is increased by reducing the lateral magnification of the lenses constituting the element lens system, and the light intensity on the image plane is adjusted so that the amount of light in the overlapping portion of each partial projection image is uniform. It is designed to have a Gaussian distribution as shown in FIG. 13 centered around the optical axis of each elemental lens system. Regarding one or more parallel arrays that are parallel to each other, flatness within a few percent can be obtained by satisfying the following conditions when the effective diameter of a lens to be described later is φ _and the pitch is a. M ₁ ×φ ₁ <a＜M ₂ ×φ ₁
(M ₁ = 1.18, M ₂ = 1.36) Using FIG. 8 a in Example 2, Example 3
Describe the optical characteristics of As in Example 2, for the first lens 40, the radius of curvature of the first surface, that is, the surface on the object side is r ₁ , and the radius of curvature of the second surface, that is, the surface on the image field side is r ₂
(Negative value in the figure) The center thickness, that is, the distance between the first and second surfaces along the optical axis, is d ₁ ', the refractive index is n ₁ ', the effective diameter of the lens is φ ₁ , and the size of the object field of view is Assuming that the size of the intermediate image 53 is φ ₀₁ and the size of the intermediate image 53 is φ ₂ , the first
The distance from the surface to the object 50 is S ₁ (negative value in the figure), the distance from the second surface of the first lens 40 to the intermediate image 53 is S ₂ ', and the lateral magnification of the intermediate image 53 with respect to the object 50 is β ₁ ( ≡−|φ ₂ /φ ₀ |) Let be the effective F number Fe on the object side. Fe, S ₁ , β ₁ , S ₂ ′, n ₁ ′ can be set in advance,
From these five set amounts, r ₁ , r ₂ , d ₁ ′, φ ₁ , φ ₀
is calculated from the ideal imaging theory. Here, since the meaning of the principal ray, which is the basis of the optical system according to this embodiment, is different from that in Embodiments 1 and 2, it will be explained. When considering a ray that enters the upper end of the first surface of the object side lens from the effective object field of view edge and a ray that passes from the effective object field of view end to the lower end of the second surface of the object side lens, the second surface exit of both rays A ray that emerges from the center after the height, becomes parallel to the optical axis, and heads toward the image field side lens is defined as the principal ray, and this ray characterizes the optical system according to this embodiment. Now, we will calculate r ₁ , r ₂ .d ₁ ′, φ ₁ , φ ₀ below, but first from the definition of F number Also, from paraxial tracking, β ₁ = 1/( ₁ +- ₁ e ₁ ′ ₂ ) S ₁ + (1-e ₁ ′ ₂ ) ...(23) However, ₁ ≡ n ₁ ′- 1/r ₁ (first (refractive power of the surface) ₂ ≡1-n ₁ ′/r ₂ (refractive power of the second surface) e ₁ ′≡d ₁ ′/n ₁ ′ Next, the principal ray of the effective incident light flux from the object passes through the second surface. The following relationship is shown based on the condition that the light is emitted parallel to the optical axis after exiting. ₂ = 2/e ₁ ' (24) ₁ = -1/S ₁ (25) Furthermore, the following relationship is required from the condition that the aperture efficiency at the required maximum angle of view becomes zero. φ ₀ =−2×S ₁ ×φ ₁ /e ₁ ′ ...(56) Finally, from the conditions for keeping the distance S ₂ ′ from the second surface of the first lens 40 to the intermediate position at an appropriate value in advance, the following A relational expression is required. S ₂ ′=1/ ₂ ……(27) The conditions of equations (22) to (27) above are r ₁ , r ₂ , d ₁ ′, φ ₁ ,
By solving for φ ₀ , we uniquely obtain the following result. r ₁ =-(n′ ₁ −1)S ₁ …(28) r ₂ =S ₁ ×β ₁ ×(1−n ₁ ′)……(29) d ₁ ′=2×n ₁ ′×S ₁ × β ₁ ...(30) φ ₀ =−φ ₁ /β ₁ (32) Next, the second lens 41 will be explained. As before, use the symbols given in Figure 8a. In the figure, the radius of curvature of the first surface of the second lens 41, that is, the surface on the object side is r ₃ , and the radius of curvature of the second surface, that is, the surface on the image field side is r ₄ (negative quantity in the figure). center thickness, that is, the first and second surfaces along the optical axis.
The thickness of the lens with respect to the surface is expressed as d ₂ ′, and the principal refractive index of the material of this lens, that is, the refractive index for a typical design wavelength is expressed as n ₂ ′. Also, the effective diameter of this lens is represented by φ ₃ , the size of the projected image with respect to the second lens on the projection plane is represented by φ ₄ , and this lens 4
1, the distance to the intermediate image 53 is
S ₃ (negative amount in the figure), and the distance from the second surface of the second lens 41 to the projected image is expressed as S ₄ '. The lateral magnification for the image 53 is expressed as β ₂ (≡−|φ ₄ /φ ₂ |). And the effective F on the image field side of this lens 41
Let us denote the number by Fe′. The effective F number determined from the conditions regarding the brightness of the projected image, that is, The lateral magnification β ₂ (|β ₂ |>1) of the projected image, the distance S ₃ from the intermediate image to the object side surface, and the lens back S ₄ ' to the projection plane are quantities that can be set in advance. Further, the principal refractive index n ₂ ' of the material is determined by setting the material. These set amounts Fe′,
From β ₂ , S ₃ , S ₄ ′, and n ₂ ′, the radius of curvature r ₃ of the first surface of the second lens 41, the radius of curvature r ₄ of the second surface, the lens center thickness d ₂ ′ of the second lens, and the Effective diameter of 2 lenses φ
₃ , and the effective diameter _φ4 of the projected image is determined using the ideal imaging theory based on the following conditions. First, the relationship between the lateral magnification β ₂ and the configuration data of the lens 41 is given by the following equation. 1/β ₂ = 1/( ₃ + ₄ − ₃ e ₂ ′ ₄ ) (−S ₄ ′) + (1 − e ₂ ′ ₃ ) ……(34) However, ₃ ≡n ₂ ′−1/r ₃ ( (Refracting power of the first surface) ≡1-n ₂ ′/r ₄ (Refractive power of the second surface) e ₂ ′≡d ₂ ′/n ₂ ′ Next, the chief ray of the effective incident light flux from the object is directed to the second lens. From the condition that _it is parallel to _the optical axis when _it enters the first surface _of Therefore, the following relational expression is required. φ ₄ = 2×S ₄ ′×φ ₃ /e ₂ ′ ...(37) Finally, from the conditions for keeping the distance S ₃ from the first surface of the second lens 41 to the intermediate image position at an appropriate value in advance, A relational expression is required. S ₃ = _-1/3 ...(38) The above conditional expressions (33) to (38) are expressed as r ₃ , r ₄ , d ₂ ′, φ
By simultaneously solving for ₃ and φ ₄ , we uniquely obtain the following result. _{r 3 = S 4 ' _ _} n ₂ ′×S ₄ ′×1/β ₂ ……(41) φ ₄ =−β ₂ ×φ ₃ ...(43) Therefore, in the coaxial optical system combining the first lens 40 and the second lens 41, first, the intermediate image (object diameter φ ₀ ) of the object to be projected (object diameter φ 0 ) is An image diameter φ ₂ ) is formed, and the intermediate image is then relayed by the second lens onto the projection image plane as an erect image with a projection image diameter φ ₄ . At this time, in order to consistently form the entire image of the object plane on the projection plane by arranging a plurality of coaxial optical systems each consisting of a first lens and a second lens, generally β ₁ ×β ₂ =
Note that it must be used at +1, that is, erect and at the same magnification. That is, it is necessary to consider the configuration of the first lens and the second lens so that the relationship β ₂ =1/β ₁ (44) is satisfied. With this kind of consideration, Fe′=Fe ……(45) inevitably becomes obvious. In the end, in an erect equal-magnification coaxial optical system that combines the first lens 40 and the second lens 41, the first lens 40
If β ₁ and Fe are set according to appropriate conditions, then β ₂ and Fe' of the second lens are naturally determined by equations (44) and (45). but,
The other setting values of the first lens, S ₁ , S ₂ ′, n ₁ ′, and the setting values of the second lens, S ₃ , S ₄ ′, n ₂ ′, are determined independently from each other under appropriate conditions. Good things must be noted. Now, generally speaking, if the first lens and the second lens have different configurations, two types of lenses will be produced, and it is desirable to avoid this from a manufacturing standpoint. From this point of view, the above-mentioned first lens and second lens
Conditional expression for an erect equal-magnification coaxial optical system combining lenses
As the second lens satisfying (44) and (45), a coaxial optical system in which the first lens is arranged symmetrically with respect to the intermediate image plane can be considered. Therefore, based on this idea, it becomes possible to use the first lens as the second lens. In this case, the specifications constituting the second lens are obtained from the following relationship with the specifications constituting the first lens. That is, r ₃ = −r ₂ , r ₄ = −r ₁ , d ₂ ′=d ₁ ′, n ₂ ′=n ₁ ′, φ ₃
= _φ1 , _φ4 = ₀ , _β2 =1/ _β1 , _S3 =−
S ₂ ′, S ₄ ′=−S ₁ , Fe′=Fe. This makes the projection optical system simple. Furthermore, the inventor conducted an experimental design and confirmed that the first lens and the second lens may be approximately ±10% from the above conditional expressions (28) to (32) and (39) to (43). did. That is, −K ₁ ×S ₁ × (n ₁ ′−1) r ₁ −K ₂ ×S ₁ × (n ₁ ′−1) K ₂ ×S ₁ ×β ₁ × (1−n ₁ ′) r ₂ K ₁ ×S ₁ ×β ₁ (1−n ₁ ′) 2×K ₁ ×n ₁ ′×S ₁ ×β ₁ d ₁ ′ 2×K ₂ ×n ₁ ′×S ₁ ×β ₁ K ₁ ×S ₄ ′×1/β ₂ ×(1−n ₂ ′) r ₃ K ₂ ×S ₄ ′×1/β ₂ ×(1−n ₂ ′) K ₂ ×S ₄ ′×(1− n ₂ ′) r ₄ K ₁ ×S ₄ ′× (1−n ₂ ′) −2×K ₁ ×n ₂ ′×S ₄ ′×1/β ₂ d ₂ ′−2×K ₂ ×n ₂ ′ ×S ₄ ′×1/β ₂ However, K ₁ =0.9 and K ₂ =1.1. Considering these conditions, the data is shown in the following table.

【table】

[Table] In Embodiment 3, as in Embodiment 2, the basic idea is to use the inner diameter surface of the lens barrel as a so-called diaphragm extending in the optical axis direction, but regarding light entering the lens from outside the effective object field. Since the reflected light from the inner diameter surface of the lens barrel becomes stray light and adversely affects the light intensity distribution on the image plane, it is necessary to take sufficient anti-reflection measures. The antireflection measures are the same as those described in the second embodiment. As described above, in the third embodiment, by using the lens effective diameter, that is, the lens outer diameter as the basis of the light intensity distribution on the projection surface, and by providing stable reflection prevention, a compact projection device with good image performance is achieved. Next, a projection apparatus according to an embodiment of the present invention will be shown, which is specifically assembled and configured using the compound eye projection lenses shown in Examples 1, 2, and 3. Next, the most preferable projection device constructed using the compound eye projection optical system shown in Examples 1, 2, and 3 will be described. FIG. 14 is an overall view of a projection apparatus using the optical system of Example 1. The apparatus is composed of two lens blocks 81 and 82 and a mask 85. The first lenses shown in FIG. 2 are arranged and fixed in parallel to the first lens block 81 on the document side, forming a plurality of optical axes.
Further, a second lens is arranged and fixed on the second lens block 82 on the projection surface side in the same manner as the first lens block 81, and the optical axis of each second lens is aligned with the optical axis of the corresponding first lens. We are doing so. Further, bank portions 83 and 84 are formed on the projection surface side of the first lens block and on the document surface side of the second lens block, respectively, and these have openings arranged in the same arrangement as the first and second lenses. The third mask 85
It has the function of fixing the field stop 12 at the position shown in the figure and fixing the distance between the lens end surfaces of the first lens and the second lens to (S ₂ '+S ₃ ) shown in FIG. Side sectional views of the device viewed from directions A and B in FIG. 14 are shown in FIGS. 15a and 15b, respectively. The elemental lens system, which is composed of a first lens having a common optical axis, a second lens, and a mask having an aperture, respectively projects different parts of the original onto different parts on the projection plane, and performs compound eye projection. The device forms an overall image 4 of the strip-like area 3 as shown in FIG. The projection device is arranged so that the distance between the document side end surface of the first lens and the document D is S ₁ shown in FIG. 3, and the distance between the projection surface side end surface of the second lens and the projection surface P is S ₄ '. Fixed. (The fixing means is omitted from the drawings.) Also, FIG.
Shown in b. In this device, the first and second lens blocks do not have bank portions, and are fixed together through a thick plate 90 with a hole of the diameter of the bar lens formed at the bar lens arrangement position as shown in FIG. 16c. There is. By this thick plate 90, the distance between the end surfaces of the first lens and the second lens is maintained at (S ₂ '+S ₃ ) shown in FIG. 90
The walls of the hole are treated with anti-reflection treatment to prevent light reflection. It is an object of the present invention to provide a method for producing a lens block, that is, a compound eye lens device, for forming the above-mentioned projection device, with the highest mass productivity and at the lowest cost. Experiments conducted by the inventors have shown that in a projection device with the most practical size and optical performance of the projection optical system, each lens has a diameter of 1 to 2 mm and a light beam of approximately A4 size. Axial length is 10mm
It is preferable that the degree of In this case, in order to be able to project the entire image of an area the width of the document, the projection device would need to have an array of nearly 100 lenses. Although it is generally technically difficult to form a projection device capable of projecting an original image as a whole by arranging a large number of small lenses having such lens end curved surfaces, the present invention employs the following manufacturing method and configuration. This problem has been solved. Furthermore, the embodiments of manufacturing a lens block or compound eye lens device described below are applicable to all of the optical systems of the three embodiments described above. In the present invention, methods for producing a lens block, that is, a compound eye lens device, in which a large number of lenses whose length along the optical axis is longer than the effective diameter are arranged are broadly classified into two types. The first method is to first create individual bar lenses and then insert and fix them into a lens support.The second method is to create a block of lens material fixed to a lens support, or a lens material. A large number of lens curved surfaces are formed at once on a block that also serves as a lens support. The single lens in the first method is one that is made of transparent plastic such as acrylic resin, epoxy resin, polycarbonate, styrene, etc. using a compression or injection processing method, and one that is obtained by polishing a glass material. etc. As mentioned above, since a practical bar lens itself is very small, it is technically and cost-effective to make it from glass, so it is preferable to make it from transparent plastic. In the following examples, an example using acrylic will be shown. Manufacturing method 1 Manufacturing method 1 is similar to manufacturing method 2 described below, in which a plurality of single bar lenses are first created, and then they are inserted into a lens support and then integrated. First, create a single bar lens as shown in Figure 17a and b.
To explain, an acrylic rod 112 formed by a method such as injection, casting, or extrusion is placed in a mold 1 having approximately the same diameter as a bar lens.
After the acrylic rod is heated and softened, it is pressed with molds 111 and 111' having concave spherical surfaces with the radius of lens curvature (for example, r ₁ and r ₂ in FIG. 3) to create a compression bar lens 112. do. Next, to explain how to fix the bar lens, the 18th
FIG. 18B is a hollow lens support 113 made of a metal plate such as aluminum, as shown in FIG. Insert a single bar lens into each through hole as shown in . At this time, the reference stand 114 is used to align the end faces of each bar lens with respect to the optical axis direction. Furthermore, by making the height of the reference plane variable, the positional relationship between the height of the bank and the end face of the bar lens shown in Figure 15a is adjusted so that the optical relationship of image formation between the first and second lenses is maintained. do. That is, when the first and second lens blocks are combined to form a projection device, the distance between the end faces of the opposing bar lenses is set to be the distance between the single lens surfaces of the projection optical system shown in Examples 1, 2, and 3. Adjust to. However, in FIG. 18, the bank portion for the optical system of Example 1 is not shown. After inserting and arranging a plurality of bar lenses in this manner, an acrylic resin or epoxy resin 115 mixed with black pigment or dye is injected into the hollow part of the lens support 113 and hardened, as shown in FIG. 18c. The bar lens and lens support are integrated and fixed. This black pigment serves as a light absorber and prevents stray light from passing through the wall surface of each bar lens and entering the wall surface of other bar lenses. Furthermore, by using a cured resin containing this black pigment and fixing the bar lens and the lens support with a refractive index equal to or higher than that of the bar lens, or by making the wall surface of the bar lens rough. Prevents harmful flare light from being reflected. If this method is used, the performance of each individual bar lens can be checked in advance, so a compound eye lens device with high overall optical performance can be obtained. Note that in this method, the acrylic resin 115 shrinks when it hardens, so before that, prepare a plurality of partition plates in the longitudinal direction of the lens support 113, insert them so as to divide the acrylic resin 115, and solidify. It is preferable to alleviate strain caused by shrinkage. Creation method 2 As in production method 1, first create a bar lens, then insert it into a lens support and arrange it. In FIG. 19a, a through hole about the diameter of Barnes is drilled in the lens support 116 made of a uniform opaque material from the top surface to the bottom surface, and after applying adhesive to the wall surface of the through hole or the wall surface of the bar lens, the bar lens is inserted. and fix it. If the opposing surface of the bar lens wall surface is a surface that is likely to cause light reflection, such as when the material of the lens support 116 is metal, etc., the wall surface of the bar lens is made rough and there is a black space between it and the wall surface of the through hole. The antireflection layer 117 is formed by applying a pigment or by mixing a black pigment into an adhesive. The advantage of manufacturing method 2 is that, like manufacturing method 1, a highly accurate compound eye lens device can be manufactured by removing defective bar lenses in advance. In this manufacturing method, the material of the lens support 116 is preferably a metal material in consideration of mechanical accuracy. However, if metal is used, it is technically very difficult to mass-produce through-holes with high precision at the height of the lens support because the diameter is small and the depth is deep. In that case, as shown in FIG. 19b, the lens support 116 is connected to n thin metal plates 116.
₁ , 116 ₂ , 116 ₃ ... formed of 116n,
A hole with the diameter of the bar lens is made in each metal plate at the location where the bar lens will be placed by pressing or the like.
Thereafter, these metal plates are bonded together with the holes completely aligned to form a lens support. Using this method, it is possible to easily fabricate a metal lens support provided with highly accurate through holes. Also, as shown in Fig. 19c, from the beginning, the single lens 1
12 Light-absorbing or light-blocking cladding material 118 on the sides
, and then sequentially coat the lens support 11.
It may be inserted and fixed in 6'. In this case, the lens support can also be made of a transparent material. Further, it is preferable to use a resin containing a light-absorbing pigment or the like as the cladding material, and having a refractive index substantially the same as that of the lens alone. The method of forming the block by laminating thin plates and the method of covering the side surface of the lens with a cladding material having light-absorbing or light-shielding properties, which are described in the second half of this manufacturing method, can also be applied to other manufacturing methods. Production method 3 Production method 3 involves inserting a plurality of acrylic rods into a lens support and fixing them in a fixed array, and molding the end faces of the lenses at once. First, in the process shown in FIGS. 20a, b, and c, the acrylic rod 119 is fixed to the lens support with acrylic resin mixed with black pigment in the same manner as in method 1, or as in method 2. An acrylic rod 119 is fixed to a lens support made of a uniform material with a through hole.
In this case, it is not necessary to align and fix the end faces of each acrylic rod. Thereafter, molds 120 and 120' in which concave spherical surfaces having the curvatures of the first and second end surfaces of the bar lenses are arranged at the positions of the respective bar lenses are used.
Compression molding is performed by moving in the direction shown by the arrow in Figure 0d, and the lens end surfaces of all the bar lenses are created at the same time. As a result, a compound eye lens device as shown in FIG. 20e is obtained. If this manufacturing method is used, a compound eye lens device in which the lens end surfaces are on the same plane can be obtained without using the reference stand described in manufacturing methods 1 and 2, and the lens end surfaces can be molded at one time, which saves time and effort. , which is advantageous in terms of cost and mass productivity. Furthermore, by using this method, it is possible to mass produce compound eye lens devices with less eccentricity and less variation in the optical performance of each bar lens. Furthermore, molds 120, 120' for molding lens end faces
If the accuracy is good, the distance between the optical axes of the bar lenses can be obtained at a constant pitch, and since all the lens end faces are molded at once, there is no need to insert the first end face and the second end face by mistake. Manufacturing method 4 A manufacturing method with higher mass productivity that eliminates the work and effort of inserting and fixing each bar lens or acrylic rod into a lens support as in the manufacturing methods described above will be described. The lens support 121 is made of an opaque, uniform material as shown in FIG. 21a, and has a through hole formed at the position where the bar lens is arranged, or the lens support 121 is formed using the method described in FIG. 19b. As shown in FIG. 21b, the lens support 121 is covered with acrylic resin by casting or injecting an acrylic resin 122 as shown in FIG. 21c. Thereafter, in the same way as in manufacturing method 3, a compound eye lens device is made once as shown in Figure d by compression molding using molds 120 and 120' having concave spherical surfaces of the first and second end surface curvatures of the bar lens at the placement position of the bar lens. to form. If this manufacturing method is used, compared to the conventional manufacturing methods, the labor of inserting and fixing a bar lens or acrylic rod can be eliminated, and mass production can be achieved and costs can be reduced. Additionally, since it is possible to apply a large and uniform pressure during compression molding, precise lens end surfaces can be molded. In this method, it is desirable to apply an antireflection agent to the wall surface of the through hole of the lens support before injecting the acrylic. Creation Method 5 A production method that can further reduce costs than Production Method 4 is shown in FIG. As shown in FIG. 22a, acrylic layers 124 and light shielding plates 125 are alternately laminated and bonded or fused. The blocks thus formed are molded into molds 120, 120' shown in FIG. 21c.
Compression molding is performed to form barless end surfaces on the upper and lower surfaces of the acrylic layer to obtain a compound eye lens device as shown in FIG. 22b. Further, as shown in FIG. 22c, a transparent acrylic block 124' is first provided with a bar lens curved surface on its surface by compression molding, and then cutting or laser processing is performed between the bar lens pitches. A cut is made, and a light-shielding layer is formed in the cut portion using an opaque plate or inking to prevent stray light between the bar lenses. This method is the 22nd
As shown in the right view of FIG. c, a light-shielding layer may be provided first, and then the curved surface of the bar lens may be compression molded. Creation method 6 This method is similar to creation method 5. Figure 23a
A light-shielding film such as a metal foil or a plastic sheet is sequentially inserted into the notches of the light-shielding film support 202 to form an array of light-shielding films at equal intervals, and then a transparent plastic such as acrylic resin is injected and solidified, and then the central portion is inserted. The block shown in FIG. 22a is obtained by cutting. Therefore, the lens surface can be formed at once by compression molding as in manufacturing method 5. In production methods 5 and 6, if the width of the block is made equal to two rows of bar lenses, two parallel bar lens arrays can be obtained at once by compression molding, and two lens blocks each having a width of one row can be formed. By shifting the lenses by half a pitch and gluing them together, a staggered array of lens blocks can be obtained. Preparation method 7 Insert an acrylic rod into the through hole of the lens support 126 and fix it as shown in the method 4 shown in FIG. The acrylic resin protruding from the top and bottom of the injected and solidified block is removed and polished. Separately, Senbei lenses 128 and 129, which are molded by compression molding and have convex spherical surfaces having the curvature of the bar lens end surface arranged on one end surface, are assembled into a bar with each convex spherical surface portion and an acrylic portion having the width of the through hole. It is attached to the upper and lower surfaces of the aforementioned block to form a lens. At this time, a transmission-enhancing antireflection film is provided between the bonding surfaces of the Senbei lens and the block to prevent light reflection on the bonding surfaces, thereby forming a compound eye lens device as shown in FIG. 24b. If this manufacturing method is used, mass production is high, and failures in compression molding can be checked at the Senbei lens stage, reducing losses due to molding failures. In addition, in creation methods 3 and 4, the second
As shown in FIG. 5, by making the diameter φ of the through hole of the lens support body larger than the diameter φ ₀ of the bar lens, the following advantages can be obtained. In other words, even if the through-hole is formed to be somewhat parallel to the predetermined bar lens arrangement position, as shown by "α" in Fig. 25, the large diameter of the through-hole allows for compression molding. The lens end face that has been removed is included in that area, and there is no problem with substantial optical function. However, in this case, in order to prevent harmful light from entering from the surfaces 130 other than the end faces of the bar lens, it is necessary to make those surfaces 130 rough to scatter light, or to provide a light-shielding layer with paint or the like. A projection device is formed using the compound lens device thus formed, that is, the first and second lens blocks. If a projection device is to be formed using the optical system of Example 1 as shown in FIGS. 14 and 15, each lens block will have a bank part for adjusting the distance between the lenses, as shown in FIG. It is desirable that it be formed. This can be formed on the lens support itself, as shown in Figure 26a. Further, when compression molding the end face of the bar lens in manufacturing method 4, the bank portion can also be molded with acrylic material as shown in FIG. 26b. Furthermore, when creating the Senbei lens in Manufacturing Method 7, it is also possible to create a Senbei lens with an integrated bank portion as shown in FIG. 26c to form a compound eye lens device. FIG. 27 shows a method of fixing the mask 143 to a lens block made using the method described above. The mask 143 is a dowel 1 formed on the bank of the second lens block 144.
46 and the reference hole 145 for positioning.
Furthermore, fix the first lens block on top of this and
The device shown in Figure 4 is assembled. Furthermore, mask 1
In order to alleviate the difference in temperature expansion with respect to the lens block, it is preferable to divide the mask 43 into a plurality of masks 143 ₁ , 143 _{2 .} . . in the longitudinal direction as shown in FIG. Further, the compound eye lens device manufactured by the conventional manufacturing method can also be applied to a projection device using the optical systems of Embodiments 2 and 3, as shown in FIG. Manufacturing method 8 As shown in FIG. 29a, transparent plastic fibers 211 drawn to a uniform diameter are fixed with a fiber support 210 to realize a predetermined arrangement. Thereafter, the gap is filled with black plastic having approximately the same refractive index as the transparent plastic fiber and solidified. Thereafter, both ends are cut into the shape shown in FIG. 20(d), and compression molding is performed to form a bar lens surface to produce a lens block as shown in FIG. 29(b). Furthermore, when forming transparent plastic fibers, if the sides of the fibers are covered with a cladding material 212 made of black plastic material as shown in FIG. There is no problem even if it is transparent. Production example 6 and production example 8 are production methods that are extremely suitable for mass production. Furthermore, in production example 8, if the transparent plastic fibers are placed in each groove of a block in which grooves are formed at approximately equal intervals in a predetermined direction, and the curable resin is injected from above and integrated, the lens pitch can be changed. Precise compound eye lens devices can be created. This method can also be applied to other creation methods. For example, a compound eye lens device may be formed by arranging and fixing single bar lenses in each of the aforementioned grooves. Now, an example will be described below in which a projection device assembled and configured using the previous examples is applied to a compound eye device. In FIG. 30, 160 is a drum which is rotated at a constant speed in the direction of the arrow by a motor (not shown).
It has a photoreceptor 161 formed by sequentially layering a conductive base layer, a photoconductor layer, and a surface transparent insulating layer around its periphery.
The surface of this photoconductor 161 is first uniformly charged by a corona discharger 162, and the polarity is positive if the photoconductor is an N-type semiconductor, and negative if it is a P-type semiconductor. Next, the photoreceptor 161 is moved in the direction of the arrow in synchronization with the rotation of the drum 160 at a speed equal to the reciprocal of the imaging magnification multiplied by the circumferential bundle of the drum 160 (the same bundle in the case of equal-magnification image formation). The image of the original 164 placed on the transparent original table 63 is exposed to light, and this image is projected onto the photoreceptor 6 by the projection device 165.
The image is formed on 1. The area of the document 64 facing the array 65, that is, the area where the image is formed on the photoreceptor 61, is illuminated by an illumination system 166 consisting of a lamp and a reflective shade. Here, for example, by adjusting the amount of illumination light, the amount of exposure to the photoreceptor 161 can be adjusted. The photoreceptor 161 is subjected to image exposure by the projection device 165 and at the same time is subjected to a static eliminating action by a corona discharger 167 having a polarity opposite to that of the AC corona discharger 62.
As a result, a charged pattern corresponding to the optical image of the original 164 is formed on the photoreceptor 161, and the photoreceptor 161 is further uniformly exposed to light over the entire surface by the lamp 68, so that an electrostatic latent image with good contrast is formed on the photoreceptor 161. will be formed. The formed latent image is transferred to a developing device 169 such as a cascade type or magnetic brush type.
The image is visualized as a toner image. Next, this toner image is sent out from a supply means (not shown) to the roller 1.
The image is transferred onto a transfer paper 172 which is brought into contact with the photoreceptor 161 and is fed at the same speed as the photoreceptor 61 by the photoreceptors 70 and 171. In order to improve the transfer efficiency, the back surface of the transfer paper 172 at the transfer position is charged with a polarity opposite to that of the toner forming the developed image, and this is done by a corona discharger 173. The toner image transferred to the transfer paper 172 is fixed by a suitable fixing device such as a heat fixing device having a pair of rollers 174 and 175 pressed against the transfer paper, and then transported to a storage means (not shown). After the transfer is completed, the surface of the photoreceptor is cleaned by wiping off residual toner by the edge of the elastic blade 176 that is in pressure contact with the photoreceptor surface, and returns to a clean surface.
It is again input into the above-mentioned image processing cycle. Note that the discharger 167 is installed so as to remove static electricity from the surface of the photoreceptor 161 at the same time as the light image is exposed. The static electricity may be removed. In this case, lamp 168 is not necessary. Further, the photoreceptor 161 may not have a surface insulating layer. In this case, discharger 167 and lamp 168 are unnecessary. By the way, in the projection device used in the copying apparatus shown in FIG. 30, if the lens block is constructed using a metal lens support as a skeleton, the edge 190 or 191 of the second lens block is as shown in FIG. There is a risk of discharge occurring between the discharge charger or the photoreceptor 161 kept at a high potential. This problem can be solved by the following two embodiments. First, regarding the edge 190, as shown in FIG. 32, the lens end surface 181 is widened relative to the lens diameter to cover the edge. Of course, the radius of curvature of the lens end face is the same. Bar lens 1 of this example
The form 82 may be already formed when producing the first single lens in production method 2, or it may be formed by adjusting the size of the mold during compression in production method 3. It's okay.
Incidentally, the lens blocks in production methods 4 and 7 already have this effect. Further, with respect to the edge 191, insulators 183 and 183' facing and covering the fin are placed close to each other or in close contact with each other to prevent discharge. By using the manufacturing method of the present invention as described above, a compound eye lens device can be manufactured with extremely high mass productivity and at low cost, and a compound eye lens device with high precision can be obtained. Therefore, a projection device formed using a compound eye lens device obtained by this manufacturing method is capable of projecting a high quality image.

[Brief explanation of the drawing]

FIG. 1 is an overall diagram of a projection optical system related to the present invention. FIGS. 2 and 3 are diagrams showing a first type of projection optical system. FIG. 4 is a lens arrangement diagram of the first type of projection optical system. FIG. 5 is a diagram showing a mask of the first type of projection optical system. FIG. 6 is a projected view of the mask shown in FIG. FIG. 7 and FIG. 8 are diagrams showing a second type projection optical system. FIG. 9 is a diagram showing the amount of image light in the second type of projection optical system. FIG. 10 is a diagram showing a projection area in a desirable lens arrangement of the second type of projection optical system. 1st
1 and 12 are diagrams showing a third type of projection optical system.
FIG. 13 is a diagram showing the amount of light on the image plane in the third type of projection optical system. 14 and 15 are diagrams showing a projection apparatus using a first type of projection optical system. FIG. 16 is a diagram showing a projection apparatus using second and third types of projection optical systems. 17 and 18 are diagrams for explaining method 1 for manufacturing a compound eye lens device. FIG. 19 is a diagram illustrating method 2 for manufacturing a compound eye lens device. FIG. 20 is a diagram illustrating method 3 for producing a compound eye lens device. FIG. 21 is a diagram illustrating method 4 for producing a compound eye lens device. FIG. 22 is a diagram illustrating method 5 for manufacturing a compound eye lens device. FIG. 23 is a diagram illustrating method 6 for producing a compound eye lens device. FIG. 24 is a diagram illustrating method 7 for manufacturing a compound eye lens device. FIG. 25 is a diagram illustrating an example in which the diameter of the hole in the block is larger than the effective diameter of the bar lens. FIG. 26 is a diagram showing an example of creating a bank part. Second
FIG. 7 is a diagram illustrating an example of creation for positioning a mask. FIG. 28 is a diagram illustrating an example of fabrication for alleviating the difference in temperature expansion between the block and the mask. FIG. 29 is a diagram illustrating example 8 of creating a lens block. 30 is a diagram showing a copying apparatus using a projection device; Figure 31, 3rd
FIG. 2 is a diagram showing an embodiment for preventing discharge in a copying machine. In the figure, 1...first lens, 2...second lens, 25...mask, 26...aperture, 81...first lens block, 82...second lens block, 83, 84...bank Part, 120, 120'...
... Compression type, 125 ... Light shielding plate, 12
8... Senbei lens, 160... Drum, 16
7... Corona discharger, 183... Insulator.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a compound eye lens device in which a plurality of bar lenses whose length along the optical axis direction is longer than the effective diameter of the lens are arranged in a predetermined direction, comprising: A step of inserting and fixing transparent rods into the through-holes of the lens support body in which through-holes are formed in a row; 1. A method for manufacturing a compound eye lens device, comprising the step of pressing the transparent rod using a plurality of arranged molds to mold the end surface of the transparent rod into a bar lens surface.