JP2805626B2 - Memory device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a memory device that optically reads a signal from a memory plate on which a signal is recorded as a fine optical pattern on a transparent substrate.

[Summary of the Invention]

According to the present invention, in a memory device in which a memory plate is disposed between a light source and a light receiving element, and a signal recorded on the memory plate is optically read, a signal read by the light receiving element is read for each address. By performing the binarization processing with a threshold value set by data stored in advance, a fine optical pattern can be read well at all addresses, and the recording capacity can be improved. is there.

[Conventional technology]

2. Description of the Related Art Conventionally, as a memory device, there are a semiconductor memory that can be accessed at a high speed such as a ROM, and a disk memory such as a magnetic disk and an optical disk.

However, the semiconductor memory has a short access time but a small storage capacity. On the other hand, although the disk memory has a large storage capacity, it is inevitable that the head for recording / reproducing becomes large, so that it takes time to send the head to a desired position. After completion, slight movement due to the inertia of the head occurs, so that it takes time until the head comes to a standstill, and the access time becomes longer.

Accordingly, the present applicant has previously proposed a memory device as described below (see Japanese Utility Model Application No. 63-45709).

FIG. 3 shows the overall configuration of the memory device.
In FIG. 1, (1) is a light source (not shown) that emits parallel light by an optical system such as a built-in lens.

(2) is an image sensor formed of a CCD, and (2a) is its light receiving unit. Then, between the light source (1) and the image sensor (2), a memory plate (3) and a filter plate (4) are arranged in an overlapping manner. For example, the filter plate (4) is a light source (1)
On the side, the memory plate (3) is arranged on the image sensor (2) side, but the reverse may be adopted.

The memory plate (3) is a device in which signals are recorded as minute optical patterns (3a) on a transparent substrate such as a glass flat plate. This optical pattern (3a), as shown in FIG.
This is a 1 μm square light transmissive or non-transmissive pattern, arranged at 1 μm intervals in the column direction and the row direction, each corresponding to a 1-bit signal. For example, on a 10 mm square transparent substrate, 10,000 such optical patterns (3a) are formed in the column direction and the row direction, respectively, and a memory of 100 Mbits is formed. This optical pattern (3a) is formed by, for example, the following photo process. That is, a photosensitive material as a light shielding material is applied to a glass flat plate, then irradiated with a laser beam through a mask having a pattern corresponding to a recording signal, and then washed to remove unnecessary photosensitive material. Is done.

As the filter plate (4), a light transmitting portion (4a) is formed on a transparent substrate such as a glass flat plate. This light transmission part (4a)
Is 1 μm square as shown by the broken line in FIG. The 545 × 545 light transmitting portions (4a) are arranged at an interval of 18 μm in both the column direction and the row direction, and correspond to an optical pattern (3a) shifted one row in the column direction and one column in the row direction. Are arranged as follows. Also, this light transmission part (4a)
5 corresponds to a substantially central portion of each light receiving section (2a) of the image sensor (2) as shown by a two-dot chain line in FIG. Therefore, the horizontal and vertical pixel pitch of the image sensor (2) is Becomes Here, the X-axis and the Y-axis are coordinate axes of rectangular coordinates for indicating the memory address of the memory plate (3) and the position of the light transmitting portion (4a) of the filter plate (4), and the H-axis and the V-axis are image pickup devices ( It is a coordinate axis for representing the pixel position (address of the light receiving section (2a)) of 2). The light transmitting portion (4a) is also formed by a photo process, for example, similarly to the optical pattern (3a) of the memory plate (3) described above.

In FIG. 3, reference numeral (5) denotes an actuator, and the memory plate (3) is sequentially moved by 1 μm in the X-axis direction by the actuator (5).

In the above configuration, the parallel light from the light source (1) is supplied to the filter plate (4). The light passing through each light transmitting portion (4a) of the filter plate (4) is received by the light receiving portion (2a) of the image sensor (2) via the memory plate (3). In this case, the optical pattern (3a) facing each light transmitting part (4a) is a light transmitting pattern (hereinafter, referred to as a light transmitting pattern (3a)).
The light is received by the light-receiving portion (2a) when the light-receiving portion (2a) is a light-transmitting pattern, but does not reach the light-receiving portion (2a) when the light-receiving portion (2a) is a non-transmitting pattern (hereinafter, a non-transmitting pattern).

Therefore, as shown in FIG. 5, each light transmitting portion (4a) of the filter plate (4) has "0" of the memory plate (3).
Corresponds to the optical pattern (3a) at the address 0,
When the memory plate (3) is at the origin, the image sensor (2)
Thus, a signal represented by the optical pattern (3a) at the address 0 indicated by "0" on the memory plate (3) is obtained. In this case, the number of signals is output by the number of pixels of the image sensor (2).

Next, the memory plate (3) is moved in the X direction by 1 μm by the actuator (5), and the first address indicated by “1” of the memory plate (3) is applied to each light transmitting portion (4a) of the filter plate (4). If the optical pattern (3a) of the memory plate (3a) corresponds, a signal represented by the optical pattern (3a) of the first address indicated by "1" on the memory plate (3) is obtained from the imaging element (2).

Similarly, by moving the memory plate (3) in the X direction at 1 μm intervals by the actuator (5), the second to third addresses indicated by “2” to “324” from the image sensor (2).
Signals represented by the optical pattern (3a) at address 24 are sequentially obtained. In this case, "0" to "324" of the memory plate (3)
In order to obtain a signal represented by the optical pattern (3a) at addresses 0 to 324, the distance the memory plate (3) moves is at most 324 μm.

According to the memory device shown in FIG. 3, the memory capacity is large, all optical patterns (3a) can be scanned by a slight movement of the memory plate (3), and the access time is short. .

By the way, in order to further increase the memory capacity, it is conceivable to arrange a plurality of sets of the memory plate (3) and the filter plate (4) as shown in FIG. In this case, the optical pattern (3a) at the address 0 indicated by “0” on the memory plate (3) is a transmission pattern. Note that (6) is an actuator for selecting a memory plate.

In such a configuration, the optical pattern (3a) of address 0 indicated by “0” of the memory plate (3) corresponds to each light transmitting portion (4a) of the filter plate (4). ) At the origin, the parallel light from the light source (1) passes through the stacked memory plate (3) and filter plate (4) and is received by the light receiving section (2a) of the image sensor (2). . Therefore, in this state, by sequentially moving the predetermined memory plate (3) from which a signal is to be read out by the actuator (5), signals from the first address indicated by "1" to the 324th address indicated by "324" are imaged. Obtained from element (2).

[Problems to be solved by the invention]

By the way, when a plurality of sets of the memory plate (3) and the filter plate (4) are stacked and arranged as in the example of FIG. 6, the amount of light incident on the light receiving portion (2a) of the image sensor (2) is reduced. There was a problem of non-uniformity depending on the state of (3). That is, the optical pattern on each memory plate (3) needs to be read as a binary signal of a high-level signal "1" or a low-level signal "0". If the number of layers stacked with (4) is large, the amount of light incident on the light receiving portion (2a) becomes non-uniform depending on the position of the optical pattern to be read, depending on the state of the memory plate (3) and the filter plate (4). It becomes difficult to distinguish the signal.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to enable a recording signal to be read satisfactorily even when the number of layers is increased.

[Means for solving the problem]

As shown in FIGS. 1 and 2, for example, the present invention provides a light source (1), a memory plate (3) on which a signal is recorded as a fine optical pattern on a transparent substrate, and a memory from the light source (1). A light receiving element (2) for receiving a light beam passing through the plate (3), a filter plate (4) having a light transmitting portion formed thereon,
Signal processing means (11) to (17) for performing signal processing of an output signal from the light receiving element (2), wherein an output signal from the light receiving element (2) is divided by the signal processing means (11) to (17) into two. The threshold for performing the quantified signal processing is determined from data stored in advance for each address of the optical pattern.

[Action]

According to such a configuration, since the threshold value for binarization determination is set for each address of the optical pattern based on the data stored in advance, the optimum threshold value is set at each address, and the data is recorded in a pattern. Signals of all addresses can be reliably read and determined.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIG. 1 and FIG.

FIG. 1 is a configuration diagram showing the entire memory device of this example. In FIG. 1, parts corresponding to those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In this example, after the parallel light emitted from the light source (1) is made incident on the lens (7), it is made incident on the filter plate (4) and the memory plate (3). This lens (7)
A plurality of small-diameter condensing lenses are arranged vertically and horizontally and fixed together. Each light-receiving part (2
Each condenser lens is arranged at intervals corresponding to the pixel pitch in a). In this case, for example, the light source (1) of each condenser lens
The surface (7a) on the side is a convex surface having a diameter of 18 μm and a radius of curvature of 600 μm, and the surface (7b) on the filter plate (4) side is a radius of 170 μm.
, A lens thickness of 130 μm, and a refractive index n = 1.5. By doing so, the parallel light from the light source (1) incident on the lens (7) is reduced to a light beam of 5 μm, and the output of the light beam is increased 10 times or more.

In this example, a plurality of sets of the filter plate (4) and the memory plate (3) are stacked, and each filter plate (4) corresponds to the pixel pitch of the light receiving section (2a) of the image sensor (2). Light transmitting portions (not shown) are provided at predetermined intervals, and an optical pattern (3a) whose transmittance changes according to a recording signal is formed on the surface of each memory plate (3). Each memory plate (3) is provided with a memory plate select actuator and a memory plate actuator (not shown) as in the prior art.
Is movable. Then, the image sensor (2) is arranged at a position where the light beam transmitted through each filter plate (4) and the memory plate (3) reaches.

Next, FIG. 2 shows the configuration of an output signal processing circuit of the image sensor (2). The signal charge corresponding to the amount of light received by each light receiving section (2a) of the image sensor (2) is converted into a drive circuit ( By supplying the horizontal drive pulse H, the vertical drive pulse V, and the reset pulse R from 11), the address of the light receiving section (2a) read out is controlled. That is, the image sensor (2) is reset every time the reset pulse R is supplied, and is supplied with the horizontal drive pulse H and the vertical drive pulse V, as in the case of outputting the normal image signal. ) Sequentially outputs the signal charges accumulated by light reception. Then, the signal charges output from the image sensor (2) are supplied to an output circuit (12),
The output circuit (12) converts the signal charge into a voltage signal, and supplies the converted voltage signal to a comparison signal input terminal of the comparator (13).

Further, a vertical drive pulse V and a reset pulse are supplied to the horizontal counter (14), and the vertical drive pulse V and the reset pulse R are supplied to the vertical counter (15). The horizontal counter (14) and the vertical counter (15) count the horizontal and vertical address positions (positions of the light receiving section (2a)) of the signal charges read from the image sensor (2).
Memory for setting count signal to threshold level (16)
To supply. This threshold level setting memory (1
6) has a light receiving unit (2) at each address position of the image sensor (2).
This is a memory in which a threshold level is stored in advance for each a). This threshold level setting memory (16)
For example, a reference pattern position is provided in the optical pattern of each memory plate (3), and after assembling the memory device, the light receiving unit (2a) at each address position is used to store the memory plate (3). Light source transmitted through the reference pattern position (1)
Then, the amount of incident light is detected by inputting a light beam from the optical disk, and threshold level data is stored for each address as a value proportional to the amount of incident light.

And this threshold level setting memory (16)
The threshold level data at the corresponding address is read out from the horizontal and vertical count signals supplied to the digital and analog signal converter (17), and is converted into an analog voltage signal. Then, this voltage signal is supplied to the reference signal input terminal of the comparator (13). The output signal of the comparator (13) is output to a binary signal output terminal (18).
To supply.

In the above configuration, when reading a signal recorded as an optical pattern of the predetermined memory plate (3), the predetermined memory plate (3) is first moved by the memory plate select actuator and the actuator, and the filter plate (3) is moved. 4) A predetermined pattern is positioned in the light transmitting portion. Then, light is emitted from the light source (1), and light transmitted through the corresponding optical pattern is made incident on the image sensor (2). At this time, a voltage signal corresponding to the amount of received light output from the imaging element (2) is supplied to a comparison signal input terminal of the comparator (13), and a light-receiving unit ( The voltage signal as the threshold level data of the address 2) is supplied to the reference signal input terminal of the comparator (13). Therefore, the comparator (13) detects whether the voltage signal output according to the amount of received light is higher or lower than a threshold level set for each corresponding address, and when the voltage signal is higher than the threshold level, the high-level signal " 1 ", and outputs a low level signal" 0 "when it is lower than the threshold level. Therefore, as an output signal obtained at the output terminal (18),
It becomes a binary signal of a high level signal "1" or a low level signal "0", and a signal recorded as an optical pattern on the memory plate (3) is read out as a binary signal.

As described above, according to this example, when reading the optical pattern on the memory plate (3), the determination of the recording signal is performed by the image pickup device (2).
This is performed at the threshold level set for each address of each light receiving section (2a), so that appropriate determination can be made according to the state of the light receiving section (2a) of each address and the optical path reaching this light receiving section (2a). Thus, the recorded signal can be reliably read as a binary signal. Further, when a plurality of filter plates (4) and memory plates (3) are stacked as in this example, a large amount of non-uniformity of the amount of light incident on the light receiving section (2a) occurs. Can be read out, the number of layers of the filter plate (4) and the memory plate (3) can be increased, and the recording density and the recording capacity can be improved.

Further, in this example, since the light from the light source (1) is condensed by the lens (7) and then incident on the optical pattern of the memory plate (3), the amount of light reaching the light receiving section (2a) increases. However, the signal reading can be performed stably, and the irradiation time of the light from the light source (1) can be shortened, and the reading time can be shortened.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

〔The invention's effect〕

According to the present invention, even if a plurality of filter plates and memory plates are stacked, the fine optical pattern of each memory plate can be read well at all addresses, so that the number of stacked layers can be increased, and the recording density and recording density can be increased. There is a benefit that capacity can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram of a signal readout circuit of the embodiment of FIG. 1, FIG. 3 is a block diagram of an example of a memory device, and FIGS. FIG. 6 is a diagram illustrating an example of a memory device. (1) is a light source, (2) is an image sensor, (2a) is a light receiving unit,
(3) is a memory plate, (3a) is an optical pattern, (4) is a filter plate, (7) is a lens, and (16) is a threshold level setting memory.

Claims (1)

(57) [Claims] 1. A light source, a memory plate on which a signal is recorded as a fine optical pattern on a transparent substrate, a light receiving element for receiving a light beam from the light source through the memory plate, and a light transmitting portion are formed. And a signal processing means for performing signal processing of an output signal from the light receiving element, a threshold for performing a binary signal processing on the output signal from the light receiving element by the signal processing means, A memory device characterized in that it is determined from data stored in advance for each address of the optical pattern.