JPH0973002A - Parallel beam forming device, plane light source device, multidisplay device and production of spherical lens array - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a plane light source device which is small in size and light in weight and contributes to a cost reduction by providing this device with a pinhole means having plural pinholes and a spherical lens array consisting of plural spherical lenses. SOLUTION: This parallel beam forming device 2 is composed of a pinhole plate 3 having the plural pinholes 4 and the spherical lens array 5 consisting of the spherical lenses 5a to 5c arranged at every pinhole. The light rays 6, 7a radiated from a plane light source 1 are made incident on the pinholes 4 directly or after multiple reflections between light reflection surfaces 3b and 1a. The incident light on the pinhole 4 is made incident in the spherical lens 5a arranged thereon. The light 9a progresses in the spherical lens 5a, is refracted to the inner side and is emitted as approximately parallel beams 9b. The spherical lens array 5 consists preferably of the spherical lenses having a concentric refractive index distribution and having the refractive index larger inwardly.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a parallel light forming device,
The present invention relates to a flat light source device, a multi-display device, and a method for manufacturing a spherical lens array.

In recent years, an image device having an extremely large screen for the purpose of public display for providing a large number of viewers indoors and outdoors with public facilities such as public offices, museums, public facilities such as museums, hotels, event halls, and amusement parks. The demand for is increasing.

As one of the main large-screen image devices that meet such demands, a configuration in which a plurality of display units are arranged in a matrix and each display image is slightly enlarged and arranged on the screen without any space There are multiple display devices. This multi-display device requires a flat light source that emits substantially parallel light (hereinafter referred to as a flat light source device) as a light source provided corresponding to each display unit. Improvements in methods are desired.

[0004]

2. Description of the Related Art As a large screen image device for public display as described above, a projection type display device for enlarging and projecting an image on a screen and a plurality of small display units arranged in a matrix form a large screen. There is a multi-display device that does. Of these, the latter device is particularly suitable for applications where a device with a small depth is desired.

This multi-display device is a device in which small display units are arranged in a matrix form to have a large screen, and has a feature that the depth can be made smaller and the device can be made thinner than the magnifying projection type device. As the display unit, various display devices such as CRT, LCD and PDP are used. However, since each of these display units has a non-displayable area around the display screen (hereinafter, this area is referred to as a frame), when arranged in a matrix, the frame becomes a grid-like joint. There was a drawback that it impaired the sense of unity on the screen.

Therefore, in order to solve this drawback, a plurality of display images are enlarged and projected on a single screen by using a lens optical system, and are arrayed so as to eliminate the gaps at the boundary portions. Devices without joints have been developed.

The mainstream of such "enlarged projection type jointless multi-display" is the application of a rear projection type display device. However, the optical path length is increased in order to enlarge a small display device by several to ten or more times. Has to be long, resulting in a very large depth of the device. Further, for the purpose of reducing the depth, an apparatus using a method of arranging a mirror inside the apparatus and bending the optical path has been developed, but the depth cannot be made sufficiently small.

Therefore, in order to solve such a depth problem, the transmissive display device, the backlight, and the display image are slightly enlarged (for example, about 1.2 times) to the extent that the frame size can cover the display image. In order to achieve this, a projection-type multi-display device has been devised which is combined with an “enlarged image forming optical system with a short optical path”. The structure of this multi-display device will be described with reference to FIG.

In the figure, reference numeral 150 denotes a transmissive display means, which is normally an LCD. Reference numeral 100 is a flat light source device as a light source, 151 is an enlarged image forming optical system, and 152 is a screen.

The light emitted from the light source 100 is the LCD 1
The light is transmitted through 50 to be modulated, and is enlarged and arranged on the screen 152 by the magnifying and image-forming optical system 151 without a gap to form a large screen display without joints. Here, since the magnifying image forming optical system 151 needs to form the image displayed on the LCD 150 on the screen 152 with a short optical path length, for example, an erect image forming system 151 of equal magnification such as a gradient index lens array is used.
A structure in which a and a Fresnel concave lens 151b for image enlargement are combined is used.

Here, the erect image forming system 151a of the same size has a normal opening angle of several degrees to ten and several degrees with respect to the normal to the incident surface. This opening angle has the following two meanings. One is that the incident light to the erecting image forming system 151a does not need to be a perfect parallel light, but may be a substantially parallel light having a spread of about the opening angle (several degrees to ten and several degrees). That is good. Therefore, the erecting imaging system 15
The condition of the light emitted from the light source 100 that determines the angular distribution of the light incident on 1a is relaxed. Normally, the configuration of an optical system that forms true parallel light is rather difficult, but an optical system that forms substantially parallel light of this level is easy to construct.

Secondly, a light ray having an incident angle larger than this opening angle becomes a useless light which does not contribute to image formation even if it is incident. Therefore, for example, when the light source 100 is a completely diffused light source, the amount of light rays that reach the screen and form an image is only a few% of the total light amount of the light source, resulting in extremely low efficiency.

Therefore, the light source 100 is a parallel light in order to limit the emission angle of the light ray 160 within the above-mentioned aperture angle (several degrees to several tens of degrees) on the emission surface side of the plane light source 101 which is close to a perfect diffusion light source. It is necessary to arrange the forming devices 102 to form a combined structure. Light source 100 configured as such
The state of the light emitted from is shown in FIG. The light emitted from the normal planar light source 101 and emitted in all directions is subjected to substantially parallelization processing by the parallel light forming device 102, and becomes light having a strong directivity as indicated by 160a and 160b. The emission angle of this light is generally parallel light limited to the range of several degrees to ten and several degrees.

At present, as the parallel light forming device 102, as shown in FIG. 6, a conical transparent body (hereinafter referred to as a conical pin) 170a is formed on a pinhole plate 103 having a large number of pinholes 104. A structure in which they are inserted and arranged in a plane is used. In the figure, the conical pin 17
Although 0a is not completely inserted into the pinhole 104, it is actually inserted so that both are closely attached. This inserted state and conical pin 170a
The detailed shape of is shown in the sectional view of FIG.

Here, the conical pin 170a has flat end surfaces 176a and 176b at both end portions, and the narrow end surface 17 is formed.
6a is inserted into the pinhole in the pinhole plate 103,
The end surface 176a is arranged to be substantially flush with the lower surface of the pinhole plate 103 or to slightly project. On the incident light side surface of the pinhole plate 103, a light reflecting surface (not shown) is formed as described above.

Further, the formation of substantially parallel light will be described with reference to FIG. The light rays 172a and 172b incident on the conical pin 170a from the end surface 176a are repeatedly totally reflected on the side surface of the transparent conical pin 170a, and the angle between the normal line and the light ray becomes smaller each time, and at the time of emission from the large end surface 176b. Rays 173a, 1 with sufficient parallelism
It is 73b.

Light rays 171a and 171b which are incident from the end surface 176a are reflected by a light reflecting surface (not shown) formed on the surface of the pinhole plate 103 on the incident light side, and are reflected by a flat light source (not shown). ) Side, and is reflected by another light reflecting surface (not shown) formed on the back side thereof. Then, multiple reflection is repeated between these two light reflecting surfaces facing each other, and then the light is incident on the end surface 176a. In this way, the ratio of the light emitted from the flat light source (not shown) entering the conical pin 170a (that is, the light utilization rate).
Can be quite large.

[0018]

The array of conical pins (conical transparent body 170) as described above (170 in FIG. 6) is very effective in collimating light rays, but the individual conical pins are not effective. Since 170a has an elongated and pointed shape, a complicated process is required for its manufacture, resulting in high cost.

For example, conical pins 170 arranged in a plane
When the array 170 of a is integrally molded, it is very difficult to release it from the molding die, and even if it is possible to integrally mold it, the tips of a large number of conical pins 170a are pinned to the pins of the pinhole plate 103. The work of inserting it into the hole 104 is also extremely difficult.

Therefore, in actuality, an array of conical pins 170a as shown in FIG. 8A or an array of conical pins 175 as shown in FIG. Although the method of inserting into the hole plate is adopted, in each case, the number of conical pins 170a to be used is very large, so that the unit cost of the member is high, and also the arrangement work requires a lot of time, and the total cost is high. It has the drawback of becoming a thing.

On the other hand, the conical pin 170a is required to have a sufficient length in order to form substantially parallel light having an angular distribution of less than ten and several degrees. Usually, the conical pin 170a has a large end face (1 in FIG. 7).
About ten times the diameter of 76b) is required. In particular,
The conical pin 170a having two end surfaces (176a and 176b in FIG. 7) having diameters of 1.5 mm and 5 mm and a length of about 60 mm is required. Therefore, this conical pin 170
The array 170 of a has the drawback of being large and heavy.

As a result, the flat light source device using such a conical pin also has the drawbacks of high cost, large size and heavy weight. It is an object of the present invention to solve these problems, to provide a flat light source device that is small in size, lightweight, and can be manufactured at a low cost.

[0023]

In order to solve the above problems, the first invention is directed to a pinhole means having a plurality of pinholes for limiting the incident light, and the light emitted from the pinholes. A parallel light forming device comprising: a spherical lens array composed of a plurality of spherical lenses for light, and the spherical lenses being arranged corresponding to the pinholes.

The spherical lens referred to here includes not only a spherical lens but also a lens having a partially spherical portion such as a hemisphere or a partial sphere. A second invention is a light source, a pinhole means having a plurality of pinholes for limiting light incident from the light source, and a spherical lens array including a plurality of spherical lenses having light emitted from the pinholes as incident light. , The light source has a light reflecting surface on the back surface, the pinhole means has a light reflecting surface on the incident light side, the spherical lens is arranged corresponding to the pinhole, the light emitted from the light source, Provided is a flat light source device characterized in that the light is directly or reflected between two light reflecting surfaces sandwiching a light source to enter a pinhole, and is transmitted through a spherical lens to be emitted.

A third aspect of the present invention uses a pinhole plate having a recess and a pinhole corresponding to each spherical lens and a guard plate for preventing the spherical lens from rolling out from the peripheral portion. A method for manufacturing a spherical lens array, characterized in that a plurality of spherical lenses are placed in a hole plate and the spherical lenses are stored in the depressions by tilting, rocking or vibrating.

With respect to the first invention, it will be described with reference to FIG. 1 that substantially parallel light can be formed by using a spherical lens and a pinhole. The details of the structure of FIG. 1 will be described later as a first embodiment, but here, the function of making light incident on the spherical lens 5a from the pinhole 4 in the drawing into substantially parallel light will be described.

In FIG. 1, the light incident from the pinhole 4 into the spherical lens 5a passes through the spherical lens 5a as shown by 9a, and is refracted in the direction of 9b (inward) and emitted. Become. Here, the angle between the light 9a that enters and passes through the spherical lens 5a made of a material having a refractive index n and the normal direction of the pinhole plate 3 is θ, and the light 9b emitted from the spherical lens 5a and the normal line When the angle formed by the direction is θ ′, the relationship between θ and θ ′ is represented by n × sin θ = sin (2θ−θ ′) ──────.

On the other hand, the angle θ that a ray incident from the pinhole within the range of ± 90 ° can take in the spherical lens 5a is −sin ⁻¹ (1 / n) ≦ θ ≦ sin ⁻¹ (1 / n ) ───── ───────────────────────────────────────

Further, by using the relational expression of the value of the refractive index (n = 1.5) and the equation, the angle θ ′ of the emitted light is −11.2 ° ≦ θ ′ ≦ 11.2 ° ── ─── get

That is, even if the light incident on the pinhole 4 from the flat light source 1 is distributed at an angle of ± 90 °, the angle θ ′ of the light emitted from the spherical lens 5a is ± 11. The light is substantially parallel light limited to an angle of 2 °. As described above, good substantially parallel light can be formed by using the spherical lens and the pinhole.

Therefore, according to the first aspect of the invention, a spherical lens (for example, a diameter of about 5 mm) is used as a means for collimating a light beam, instead of a conventional conical pin (for example, a large end surface has a diameter of about 5 mm and a length of about 60 mm). Can be used, the size can be reduced and the weight can be reduced.

Further, according to the second aspect of the present invention, by providing two kinds of light reflecting surfaces that sandwich the light source, it is possible to increase the utilization rate of the light entering the pinhole from the light source (this utilization rate). Is almost equivalent to the conventional device using a conical pin).

Next, according to the third aspect of the present invention, a plurality of individually formed spherical lenses are placed in a pinhole plate having depressions and pinholes corresponding to the arrangement positions of the spherical lenses, and the pinholes are placed. By tilting, swinging, or vibrating the plate, each spherical lens can be stored in the recess, and a spherical lens array having a desired function can be formed. This is because each spherical lens is point-symmetrical, so it is not necessary to consider the angle of storage in the recess, so it is sufficient to specify only the storage position, and that position depends on the preformed recess. This is possible because it is set automatically. This makes it possible to easily form a desired spherical lens array having a pinhole plate.

Further, according to the third invention, there is a feature that the shape of the boundary portion between the adjacent spherical lenses can be made accurate. As another manufacturing method, there is a method of molding the lens array in an integral shape, but when such a method is used, it is very difficult to accurately release the lens array from the molding die. In particular, with respect to the boundary portion between adjacent spherical lenses, a manufacturing method by integral molding is not preferable because a problem such as a distortion of the shape occurs and the performance is deteriorated.
As described above, according to the third invention, not only the desired spherical lens array can be easily formed, but also the boundary between the adjacent spherical lenses can be accurately formed (the processing accuracy is high). .

Further, since this manufacturing method is extremely simple as compared with the above-described conventional method of manufacturing the conical pin array, the manufacturing cost of the parallel light forming device can be greatly reduced.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. [First Embodiment] As a first embodiment of the present invention, a configuration example of a flat light source device will be described with reference to a sectional view of FIG.

In the figure, the flat light source device comprises one flat light source and two parallel light forming devices. Here, the flat light source 1 is composed of a surface light source converting means 1b and a light reflecting surface 1a, and the surface light source converting means 1b is usually composed of a plurality of fluorescent tubes and a light diffusing plate. From this surface light source forming means 1b, 6, 7
As indicated by a, light is emitted in various directions, and light having a substantially uniform intensity is emitted on the emission surface of the surface light source conversion means 1b. In addition, the light that has traveled to the back surface becomes light that is reflected by the light reflecting surface 1a and is emitted from the emitting surface again.

The parallel light forming device 2 for substantially parallelizing the light incident from the flat light source 1 and emitting the light is provided with a plurality of pinholes 4.
And a spherical lens array 5 including spherical lenses 5a to 5c arranged for each pinhole. A light reflecting surface 3b is formed on the incident light side of the pinhole plate 3.

Here, the light 6, emitted from the flat light source 1,
There are two types of modes in which 7a enters the pinhole 4. One is a mode in which light is directly incident as shown by 6, and the other is a mode in which light is multiplexed as shown by 7b and 7c between two light reflecting surfaces 3b and 1a as shown by 7a. In this mode, the light is reflected and then enters the pinhole 4. Regarding the ratio of the amount of light of both, the light of the latter mode is overwhelmingly larger. That is, by providing these two light reflecting surfaces 3b and 1a, the proportion of light incident on the pinhole 4 is made extremely high (order of magnitude). The operation of such two light reflecting surfaces 3b and 1a is the same as that of the conventional conical pin. Further, as the light reflecting surfaces 3b and 1a, various forms such as a specular reflecting surface, a diffuse reflecting surface, and a combination thereof can be used.

The light incident on the pinhole 4 is incident on the spherical lens 5a arranged thereon. This light travels in the spherical lens 5a as indicated by 9a, for example, and is refracted inward and emitted as indicated by 9b. On the basis of the action of refracting inward, light limited to a narrow angle range (± 11.2 °) as shown in the result of the above formula, that is, substantially parallel light is emitted.

Such a flat light source device has a spherical lens array 5 as a constituent element instead of the conventional conical pin.
Is used, it is possible to reduce the size and weight.

[Second Embodiment] As a second embodiment of the present invention, a method of manufacturing a spherical lens array will be described with reference to FIGS. 1 and 2.

In FIG. 1, the pinhole plate 3 is composed of a substrate 3a having a recess and a member having a reflecting surface 3b. In FIG. 1, the recess is a recess formed by hollowing out the substrate 3a in a rectangular shape, and the spherical lens is stored in the recess. Since the spherical lens is point-symmetrical, there is no need to consider the angle of storage in the hollow. It suffices to be able to store it at a predetermined position regardless of the angle. Moreover, since this predetermined position is defined by the groove formed in advance, it is only necessary to put the spherical lens in the groove. On the periphery of the pinhole plate 3, a guard plate as shown by 10 is provided in order to prevent the spherical lenses 5a from rolling out when the spherical lenses are arranged.

Therefore, a plurality of spherical lenses 5a are placed in the pinhole plate 3 provided with the guard plate 10 and the pinhole plate 3 is tilted, swung, or vibrated so that the inside of the depression is depressed. The spherical lens 5a can be surely stored in the lens, and as a result, the spherical lens array 5 including the pinhole plate 3 can be completed. In this storing step, it is also easy to replenish the spherical lens 5a when it is insufficient and to remove it when it is excessive.

Therefore, the method of manufacturing the spherical lens array 5 using the pinhole plate 3 having the depression is extremely simple, and is simpler than the conventional method of using the conical pin. The cost can be significantly reduced.

It should be noted that although the shape of the above-mentioned recess has a rectangular shape as an example, it is not limited to a rectangular shape. Various shapes such as a triangular shape, a polygonal shape, and a curved surface are possible.

FIG. 2 shows a partial perspective view of the spherical lens array 5 housed in the pinhole plate 3 having the guard plate 10 formed in this way. The parallel light forming device 2 shown in FIG. 1 corresponds to a sectional view taken along the line AA of the perspective view shown in FIG.

[Third Embodiment] As a third embodiment of the present invention, a modification of the spherical lens will be described with reference to FIG.

The present embodiment is characterized in that the refractive index in the spherical lens 5a has a distribution. Here, it is configured such that it is divided into four regions concentrically, and the refractive indices n1 to n4 of the respective regions are different, and the refractive index increases toward the central portion.

N1 ≦ n2 ≦ n3 ≦ n4 When the spherical lens 5a is configured in this way, the light 11a incident from the pinhole 4 is, for example, 11b and 11b.
The light is refracted inward as shown by c, is then refracted outward as in 11d and 11e, and is refracted inward as in 11f and emitted. When this emitted light 11f is compared with the emitted light 12b in the case where all the spherical lenses 5a have the same refractive index n1, the emission position is close to the normal line 13 and the emission angle (angle with the normal line) is small. It is much smaller, and the level as a substantially parallel light is improved.

[Fourth Embodiment] As a fourth embodiment of the present invention, a modification of the spherical lens array and the pinhole means will be described with reference to FIG.

As the spherical lens array 21, one having a plurality of hemispherical surfaces 21a to 21c on the outgoing light side and having a plane portion 24 formed on the incoming light side is used. The hemispherical surfaces 21a to 21c are not limited to hemispherical surfaces, and include partially spherical surfaces.

Here, regarding the case where the hemispherical surfaces 21a to 21c are used, the relation between the thickness t of the flat portion on the lower side of the hemispherical portion and the radius R of the hemispherical portion satisfies the following condition.
If the refractive index of the material of the spherical lens array 21 is n, then if the condition of t ≦ R (n ² −1) ^1/2 ───── is satisfied, all the light incident from the pinhole 23 is The light enters the hemispherical lens 21b corresponding to the pinhole 23. When this light exits the hemispherical lens, it is refracted inward (to approach the normal line) and becomes substantially parallel.

As described above, in the spherical lens array constructed such that the incident light side is flat, the pinhole means can be formed easily. Specifically, the light blocking member 22 is formed on the flat surface portion 24. As the light shielding member 22, for example, a metal film of Ag, Al, or the like is formed by vapor deposition, sputtering, or the like, and a pinhole 23 is formed at a predetermined position on the metal film by using a photolithography technique or the like. Here, a metal film such as Ag or Al is a preferable material because it is a material having a high light reflectance.

The present embodiment is characterized in that by using such a structure and a manufacturing method, especially the manufacturing of the pinhole means can be facilitated and the manufacturing cost can be reduced. Instead of the metal film as described above, a metal plate having a pinhole formed at a predetermined position by using a photolithography technique may be used. In this case, it is necessary to align and mount the spherical lens array on this metal plate, but so to speak, it is only necessary to align and mount the two plates, so the conventional conical pin and pinhole plate mounting process (This is characterized in that the manufacturing method thereof can be simplified as compared with the case where alignment and mounting of a large number of conical pins and pinhole plates are required).

As a method of manufacturing this spherical lens array, instead of integrally molding using a mold, a plurality of spherical lenses are arranged by the method as in the second embodiment, and the lower region is made of resin. It is preferable to use a method of hardening and molding so that the lower surface thereof is flattened.

[Fifth Embodiment] As a fifth embodiment of the present invention, a multi-display device using the flat light source device of the first embodiment will be described with reference to FIG.

The flat light source device shown in the first embodiment is used as the flat light source device 100 for the multi-display device shown in FIG. In this case, as in the first embodiment, the spherical lens array 5a is used as the constituent element in place of the conventional conical pin, so that the overall size and weight of the device can be reduced. As described above, the manufacturing method can be simplified and the cost can be reduced.

[0059]

According to the inventions of claims 1 to 3 and 6,
It is possible to realize a parallel light forming device that is small and lightweight, has a simple manufacturing method, and has high processing accuracy.

According to the invention of claim 4, in addition to the above effects, it is possible to realize a flat light source device having a high light utilization rate. According to the invention of claim 5, it is possible to realize a multi-display device using the flat light source device having the above-mentioned effect.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of a flat light source device.

FIG. 2 is a partial perspective view of a parallel light forming device.

FIG. 3 is a diagram showing the action of a spherical lens having a distributed refractive index.

FIG. 4 is a sectional view showing a modified example of a spherical lens array.

FIG. 5 is a diagram showing a configuration of a multi-display device.

FIG. 6 is a perspective view showing a conventional parallel light forming device.

FIG. 7 is a sectional view showing an operation of a conventional parallel light forming device.

FIG. 8 is a diagram showing a conical pin.

[Explanation of symbols]

1 plane light source 1a light reflecting surface 1b surface light source forming means 2 parallel light forming device 3 pinhole plate, pinhole means 3b light reflecting surface 4 pinhole 5 spherical lens array 5a-5c spherical lens 6 incident light to the pinhole (directly Incident) 7a to 7c Incident light to the pinhole (incident after multiple reflection) 9a Light passing through the spherical lens 9b Light emitted from the spherical lens θ Incident angle to the spherical lens θ ′ Exit angle from the spherical lens 10 Guard Plates 11a to 11f Light, Rays 12a and 12b Lights, Rays 13 Normal line 21 Spherical lens array 21a to 21c Hemispherical surface 22 Light shielding member 23 Pinhole 100 Light source, Flat light source device 101 Flat light source 102 Parallel light forming device 103 Pinhole plate 104 Pinhole 150 LCD, transmissive display means 151 Enlarging imaging optical system 151a Erecting imaging system 151 b Magnifying optical system, Fresnel concave lens 152 Screen 160 Emitted light, rays 160a, 160b Emitted light 170 Conical pin array 170a Conical pin, conical transparent body 171a, 171b Light (light ray) 172a, 172b incident from the conical pin Light incident on conical pin 173a, 173b Light emitted from conical pin 175 Array of conical pin arrays 176a, 176b End face of conical pin n1 to n4 Refractive index R Radius of spherical lens t Thickness

Claims (6)

[Claims] 1. A collimating light forming device for collimating incident light and emitting the collimated light, comprising: a pinhole means having a plurality of pinholes for limiting the incident light; and a light emitted from the pinhole. A parallel light forming apparatus, comprising: a spherical lens array including a plurality of spherical lenses which are incident lights, wherein the spherical lenses are arranged corresponding to the pinholes. 2. The parallel light forming apparatus according to claim 1, wherein the spherical lens array is composed of spherical lenses having a concentric circular refractive index distribution and a larger refractive index toward the inside. 3. The spherical lens array has a plurality of hemispherical surfaces or partial spherical surfaces on the outgoing light side and a flat surface on the incoming light side, and the pinhole means is provided on the flat surface side of the spherical lens array. The parallel light forming device according to claim 1, wherein the parallel light forming device is formed of a light shielding member having a pinhole at a predetermined portion corresponding to each hemispherical surface or partial spherical surface. 4. A flat light source device for substantially parallelizing and emitting light emitted from a light source, the light source, pinhole means having a plurality of pinholes for limiting light incident from the light source, and the pin. The light source has a light reflecting surface on the back surface thereof, and the pinhole means reflects light on the incident light side. The spherical lens is arranged corresponding to the pinhole, and the light emitted from the light source is reflected directly or between the two light reflection surfaces sandwiching the light source, A flat light source device characterized in that it is incident on a hole and is transmitted through the spherical lens and emitted. 5. The flat light source device according to claim 4, a transmissive display device for modulating and transmitting light from the flat light source device to form a display image, and an incident light from the transmissive display device is enlarged. A multi-display device comprising: a plurality of display units having a magnifying image forming optical system for projecting; and a screen on which images projected from the plurality of display units are arranged. 6. A plurality of pinhole means provided with recesses and pinholes corresponding to the respective spherical lenses and having a guard plate for preventing the spherical lenses from rolling out from the peripheral portion on a surface having the recesses. The method of manufacturing a spherical lens array, wherein the spherical lens is placed and placed, and the spherical lens is stored in the recess by tilting, rocking, or vibrating.