HK1171278B - Surface identification system and method, object having an identification code pattern, and code reading apparatus for reading the object - Google Patents

Description

Surface identification system and method, article having identification code pattern, and code reading device for reading the article

Technical Field

The present invention relates generally to a system and method for identifying a surface, and more particularly, to a system and method for identifying a surface by reading an identification code pattern formed on the surface through light modulation caused by identifying the code pattern. The invention also relates to an article having an identification code pattern and a code reading device for reading the article.

Background

In industrial and/or consumer product applications, some electronic means are required to detect different faces of a three-dimensional article for identification and/or automatic classification purposes, such as identifying two faces of a tile (tile), or identifying six separate faces of a cube, etc. RFID (radio frequency identification) technology can be used to identify different faces of an item. In the RFID method, RFID data chips with different ID codes may be placed under each of the six faces of the cube, so that the RFID data chips on each face may be read and decoded using an RFID reader/decoder. Alternatively, bar code labels (each having a different bar code) may be affixed to the surface, and the bar codes affixed to the surface may be read for identification using a bar code scanner.

The use of RFID methods requires a separate RFID data chip on each surface of the article, and therefore the cost of using RFID technology is relatively high. In addition, mechanical assembly is required to be able to place the data chip on each side, and thus there is a possibility that an error occurs in the assembly process. For example, the data chip may be incorrectly placed on an incorrect surface, not to mention the additional labor cost of mechanical assembly.

As such, for bar code labeling technology, bar code labels need to be affixed to a surface. Again, this requires an additional assembly process, resulting in increased costs and possible errors, not to mention other problems, such as the bar code label being relatively easy to tear from the surface, making identification impossible.

Further, a barcode is an optical machine-readable representation (optical machine-readable representation) of data representing data of an item to which the barcode is affixed. Generally, barcodes represent data in black and white parallel lines of different widths and spacing. When the surface of the article is printed with a bar code, the article appears unattractive.

There is therefore a need to provide a new technique for identifying surfaces that can reduce cost and avoid errors to improve the accuracy of reading the code.

Disclosure of Invention

In order to accomplish the above-mentioned need, a primary object of the present invention is to provide a three-dimensional identification code pattern which is not torn off and can be used or made in various colors.

It is a further object of the invention to provide an identification code pattern which has additional advantages in structure and operation.

These and other objects and advantages of the present invention are achieved by providing a surface recognition system comprising:

at least one identification code pattern comprising a plurality of recesses, through holes and/or protrusions formed on a code area of the first surface, the identification code pattern being configured to correspond to the first surface or the second surface; and

a code reading device for reading the identification code pattern, the code reading device being capable of emitting light to the code area, receiving reflected light reflected from the code area to read out the identification code pattern according to the amount of reflected light of each of the plurality of recesses, through holes and/or projections, and displaying a correspondence between the identification code pattern and the first surface or the second surface.

Preferably, the recesses, through holes and/or projections are rectangular and arranged parallel to each other.

In one embodiment of the invention, the identifying the coding pattern identifies information related to the surface features according to a coding algorithm. The information is selected from the group consisting of: materials, colors, orientations, graphics, numbers, and words.

Typically, the coding region is provided on an edge of the first surface.

The light may be selected from the group consisting of: infrared, red, white, and/or blue light.

An infrared optical coupler may be used as the code reading device.

Each of the plurality of recesses, through holes, and/or projections represents a binary code "1" or "0". The identification code pattern includes a start bit and an end bit.

A second aspect of the invention relates to a method of identifying a surface, the method comprising:

providing an identification code pattern on the code area of the first surface, the identification code pattern comprising a plurality of recesses, through holes and/or protrusions formed on said code area;

emitting light rays toward the encoded region such that a portion of the light rays are reflected from the encoded region;

receiving the reflected light to read out the identification code pattern according to the amount of the reflected light of each of the plurality of recesses, through holes and/or protrusions; and

and displaying the corresponding relation between the identification code pattern and the first surface or the second surface.

A third aspect of the invention relates to an article having at least one surface comprising a coding region formed with at least one identification code pattern comprising a plurality of recesses, through holes and/or protrusions, wherein the identification code pattern is configured to correspond to the at least one surface.

A fourth aspect of the present invention relates to a code reading device for reading an identification code pattern of the above-mentioned article, the code reading device comprising:

a housing;

a power source;

a circuit electrically connected to a power source;

a device for emitting light and detecting the amount of reflected light, the device being operatively connected to the circuit;

at least one channel mounted on said housing for guiding movement of said article such that said emitting and detecting means scans said code area;

at least one holder connected to the at least one channel to receive the item;

wherein the emitting and detecting device is capable of emitting light towards the code area, receiving and detecting reflected light reflected from the code area, transmitting a signal to the circuitry for further processing to read an identification code pattern representing a correspondence with a surface based on the amount of reflected light for each of the plurality of recesses, through holes and/or protrusions.

In one embodiment of the invention, the emitting and detecting device is an infrared optical coupler.

And a cover is arranged on the shell of the code reading device. The power source is a battery and/or a suitable AC-DC power source.

The present invention provides an alternative and technique for detecting and/or identifying the surface and/or different sides of a three-dimensional article by modulating light reflection, such as modulating infrared light reflected by a three-dimensional identification code pattern on the surface directly from the surface, so that the code pattern can be read and decoded with an inexpensive infrared reader/decoder to identify the surface and/or different sides of the article without the need for additional electronic circuitry to be installed and/or further surface processing, such as printing and/or labeling, to do so.

According to the invention, the coding pattern is embedded on the surface of the article when it is formed or manufactured, thus minimizing and/or even eliminating the need for any additional components and/or assembly, which not only reduces the production costs, but more importantly it eliminates any errors during assembly when the above solution is used. Unlike bar code methods, which typically require printing black and white bar codes, the present invention can take virtually any color.

The present invention provides a solution for modulating the amplitude and/or frequency of reflected light from a surface by embedding a coding pattern on the surface. The encoded pattern can be read and decoded using, for example, a simple infrared reader/decoder for identification, classification, etc.

For a better understanding of the present invention, reference will now be made in detail to the present invention and its embodiments, taken in conjunction with the accompanying drawings.

Brief Description of Drawings

FIG. 1A shows a smooth planar surface of an article on which no identification code pattern is formed.

FIG. 1B shows the waveform of an electrical signal as it is electrically scanned across the surface of FIG. 1A using an infrared optical coupler.

FIG. 2A shows the surface of FIG. 1A having rectangular grooves.

FIG. 2B shows the waveform of an electrical signal as it is electrically scanned across the surface of FIG. 2A using an infrared optical coupler.

Fig. 3A shows the surface of a plastic block on which an identification code pattern according to an embodiment of the present invention is formed.

Fig. 3B shows the waveform of the electrical signal as it is electrically scanned across the surface of fig. 3A using an infra-red photo-coupler, where the time difference between the first two electrical pulses and the time difference between the last two electrical pulses are shown.

Fig. 4 shows some examples of identification code patterns of the present invention.

FIG. 5 illustrates a perspective view of a card reader constructed in accordance with the present invention.

FIG. 6 shows a front view of the card reader of FIG. 5.

FIG. 7A shows a perspective view of one surface of a game card having an identification code pattern formed in an encoded region of the surface and the letter "C" molded therein.

FIG. 7B shows a perspective view of another surface of the game card of FIG. 7A having an encoded region in which another identification code pattern is formed and in which the letter "D" is molded.

FIG. 8 shows a front view of a card reader of the present invention having four channels allowing four game cards to be read.

FIG. 9A illustrates a game interface displayed in a screen that is operated in conjunction with the game card and card reader of the present invention.

FIG. 9B shows an example of a card reader of the present invention in which a game card is ready to be inserted into the channel of the card reader.

FIG. 10A illustrates a second game interface displayed in a screen that is operated in conjunction with the game card and card reader of the present invention.

FIG. 10B shows the card reader of the present invention with the holder of the card reader receiving two game cards and ready to insert one game card into the channel of the card reader.

Fig. 11 is a flowchart of the text game shown in fig. 9A or fig. 10A.

Detailed Description

While the invention has been illustrated and described in terms of preferred embodiments, the invention can be implemented in numerous different configurations, sizes, and forms using a variety of materials.

When a light source is directed at a surface, whether a metal and/or plastic surface, a portion of the light is reflected from the surface. The amount of light reflection depends on the physical properties of the surface. Generally, a matte or darker colored surface reflects less light and a glossy and/or lighter colored surface reflects more light. If a light receiving sensor such as a phototransistor and/or photodiode is brought close to the surface and light is emitted onto the surface with a light source, the light receiving sensor can receive light reflected from the surface. The amount of light received by the light receiving sensor is substantially proportional to the distance between the sensor and the reflective surface, and also proportional to the light reflective properties of the surface, such as color and glossiness.

As long as the sensor is not in direct contact with the surface, thereby blocking all reflected light from reaching the sensor, or the light sensor is too far from the surface so that too little or no light reaches the sensor to cause a response, there is some reflection of light when the light is emitted towards the surface.

As is known in the art, brighter colors such as white and yellow reflect more light than darker colors such as deep blue and violet, and a high gloss machined surface reflects more light than a non-glossy machined surface.

Fig. 1A shows a flat plastic article about 2 mm thick, the surface 1 of which is smooth and free of recesses or protrusions. Fig. 1B shows an electrical signal corresponding to light reflected from the flat plastic surface when a device that emits light and detects the amount of reflected light, such as an infrared photocoupler, is energized to emit light and scan through the plastic surface 1. In FIG. 1B, the vertical axis represents voltage (in arbitrary units), which in practice may be at a level of, for example, 500 mV; the horizontal axis represents the time (also expressed in arbitrary units) when the light travels over the surface 1 of the article, which may be about 10-20 ms. FIG. 1B shows that when the IR photo-coupler is brought into close proximity to and scanned across a plastic surface, light is reflected from the surface, producing a forward pulse at the output of the IR photo-coupler. In fig. 1B, the voltage signal of the smooth surface may be regarded as a binary constant "1" or "0".

Since the amount of light reflected from the surface depends on the distance between the surface and the sensor, in addition to surface properties such as gloss and color, when a through-hole 3, for example, a rectangular through-hole, is cut to form on the surface 1 of the above-mentioned article (see fig. 2A), no surface reflects light on the through-hole 3, so that little or no light will be reflected by the through-hole 3. Thus, when an IR photo-coupler is brought into close proximity and scanned across the through-hole surface, the through-holes 3 of the surface 1 will cause amplitude modulation of the IR reflected electrical signal (as shown in FIG. 2B). That is, the via 3 sinks the smooth surface voltage signal, which may be regarded as a binary value "0" or vice versa.

Whereas in some applications it may be less aesthetically pleasing to gouge one or more through-holes in a surface, alternatively, protrusions (or hills) and/or grooves may be provided in the surface (see fig. 3A). When an infrared optocoupler is brought close to and scanned across a surface 1 with hills and/or grooves 2, the hills and/or grooves 2 on the surface 1 can effectively modulate the reflection distance between the surface and the sensor. In the case of the groove 2, the distance between the flat surface and the sensor is smaller, so that the flat surface reflects more light, while the groove 2 reflects less light because of the larger reflection distance from the surface, i.e. the larger reflection distance from the sensor. This change in the reflection distance on the surface will modulate the IR light coupler output (as shown in FIG. 3B) due to the grooves provided on the surface. This also applies to the case where the projections are formed on the surface.

By modulating the light reflection by providing the through-holes 3 and/or the grooves 2 on the surface 1 as described above, a three-dimensional coding pattern can be formed on the surface to code the surface for identification or similar purposes.

For example, a 10-digit code pattern consisting of 10 equally sized rectangular grooves may be formed on the surface 1 of the article. In this embodiment, the article is a plastic card as shown in fig. 3A, each groove 2 representing one bit, which when scanned across the code area of the code pattern using an infra-red photo-coupler results in a wave-shaped depression as shown in fig. 3B. It can be observed from the waveform shown in fig. 3B that the spacing between successive electrical pulses varies with time due to the inertia and acceleration of the scanning motion, which means that the waveform has frequency modulation in addition to amplitude modulation. As shown, the spacing between the first two consecutive electrical pulses is 3.6 milliseconds, and the spacing between the last two consecutive electrical pulses is 3.0 milliseconds. That is, from left to right in fig. 3B, the time difference between two consecutive electrical pulses gradually decreases. This information can be used to determine the speed of the scan, if desired.

In yet another embodiment, the surface of the plastic/game card may contain engraved letters and/or numbers. An identification code pattern may be included on the alphabetic card to facilitate electronic identification of individual letters and/or numbers on the card using an electronic reader. Figure 4 shows a number of injection molded plastic alphanumeric cards each carrying a 10-digit identification code pattern corresponding to different letters and/or numbers on the card. Unlike conventional printed bar codes, the 10-bit code pattern is formed when the card is injection molded, thus eliminating the need to use any additional parts and/or assembly processes to form the code pattern. The embedded identification code pattern uses 10-bit encoding, which can produce a total of 1024 code patterns. Fig. 7A and 7B show a plastic gaming card with the letters "C" and "D" and the corresponding embedded 10-digit identification code pattern molded on the top and bottom surfaces of the card, respectively. It should be noted that the coding pattern of the "C" surface may be configured to correspond to the "C" surface itself or to the "D" surface, if desired.

Referring to fig. 7A and 7B, an identification code pattern formed by grooves 2 or protrusions is provided on the edge of the surface 1, representing letters or numbers on the opposite surface, instead of the letters or numbers on the surface forming the code pattern, to facilitate reading of the code pattern by a card reader. As will be described below.

The following describes a product application for an interactive video word game in which the above-described identification coding pattern is used in conjunction with direct surface light reflection modulation.

A video word game may display a picture or video file of an animal or item on a display device, such as a television. Typically, a video word game may include an alphanumeric keypad as a user interface device for a user to enter words and/or numbers to interact within the game. Alternative user interface devices may be developed using the identification code pattern formed on the surface of the present invention. For example, the alphanumeric plastic cards shown in FIG. 4 may be used as input devices in games, rather than using a conventional "qwerty" keyboard to enter and/or spell words.

Fig. 5 and 6 show a card reader used in a word game to read the alphanumeric plastic card of fig. 4. Fig. 7A and 7B are exemplary alphanumeric plastic game cards with an identification code pattern for use with a card reader. The principles and electronic circuit design of a multimedia interactive video word game for use with the plastic card reader of the present invention may be referenced to conventional technology in the art and will not be discussed in detail herein as it is not essential to the present invention.

The alphanumeric plastic game cards of fig. 7A and 7B may have different embedded coding patterns to represent corresponding letters and/or numbers on the plastic cards. The coding pattern is formed by a plurality of grooves 2 in the surface 1. To minimize cost, the top and bottom sides of each plastic card may be individually formed to include letters and/or numbers with corresponding coding patterns. Table 1 below shows an example of binary code assignments for each alphabetic plastic card from a to Z and each numeric block from 0 to 9. Preferably, the coding pattern comprises two grooves or protrusions representing a start bit and an end bit of the coding, respectively. It should be noted that the coding pattern may have different meanings depending on the actual application.

TABLE 1

Fig. 6 shows the card reader with the cover 30 of the card channel removed. As shown, a slot 60 is provided in the lower right portion of each of the four card channels on the card reader, and an IR photo coupler is mounted behind the slots 60. The slit 60 is provided to allow the ir-photo coupler to effectively read the ir reflected from the identification code pattern as it passes through the ir-photo coupler. The typical width of the slit is slightly narrower than the width of the reflective surface of the groove or protrusion constituting the coding pattern. For example, a typical width of a reflective surface of a groove or protrusion of the code pattern on a plastic game card is about 1 millimeter, then a slit that allows an infrared light coupler of a card reader to read the code pattern may be about 0.8 millimeter. In normal use, the ir photo-coupler is hidden behind the cover 30 of the card channel, which shields the ir photo-coupler from any potential light interference from the environment.

In the exemplary card reader design, the card reader is provided with 4 card channels 10, each having its own IR photo coupler. Referring to fig. 8, to spell the word "DALE," the player finds the plastic cards D, A, L and E, respectively, and places them in the card lane one after the other in sequence. As shown, when the card slides down through the card channel 10, the card will rest in its own card holder 20 and be readily removed by the player.

In this embodiment, the identification code pattern embedded in the bottom surface of the card corresponds to the letters molded on the top surface of the card, the code area of the bottom surface being scanned as the card moves through the card channel 30 and rests in the card holder 20 after movement, and the letters on the top surface being visible. Likewise, the identification code pattern embedded on the top surface of the card corresponds to the letters molded on the bottom surface of the card. Such a configuration is a mating card reader design.

A plastic card reader housing electronic circuitry may have video and audio output jacks for connection to a video display device such as a television. After the plastic card reader is connected to the television and the power is turned on, a game menu as shown in fig. 9A is displayed on the television. In this embodiment, the menu provides two game options, and the user can select one from two different games, game 1 and game 2. To select a particular game to play, the user inserts a digital card corresponding to the number displayed on the television for that game. For example, as shown in FIG. 9B, if the user wants to play game 2, the user must find the number 2 digital card and place the digital card in the card channel 10 of the card reader. The digital card slides down through the card channel 10 of the card reader due to gravity and passes through an infra-red photo coupler disposed in the card channel; the identification code pattern formed on the card produces an amplitude modulation of the infrared reflection which is read by an infrared photocoupler through a slit 60 to produce an electrical code signal.

The coded signal from the IR photo coupler is fed through a simple analog/digital converter in the electronic circuitry and then the coded signal is input to the electronic circuitry of the card reader for processing. When the code signal is received, the electronic circuit checks whether the code is a valid code. If it is a valid code, which represents that the person playing the game selected game 2, the electronic circuitry initiates game 2 to begin playing the game and accordingly displays the game content for the person playing the game to play. For example, as shown in FIG. 10A, the gaming device may display a picture or video file of a cat and then ask the person playing the game to spell the animal's word. As shown in fig. 10B, the player needs to find the alphabetic cards and place them in and slide them through the corresponding card channels on the gaming device. The card reader of the gaming device may read and recognize the identification code pattern on the card and determine whether the person playing the game spells the word correctly. It may then provide visual and/or audio feedback to interact with the person playing the game.

FIG. 11 is a flow chart for the video word game described above. At step 100, the game begins. In step 101, the user turns on the power to start the game. At step 102, the display screen displays a game menu or interface. At step 103, the card reader detects whether any tiles (i.e., plastic cards of the present invention having an identification code pattern) are inserted into the card input recess. If no card is inserted, the game returns to step 102. If there is an inserted card, the card reader detects whether the card is a number 1 card at step 104.

If the card detected at step 104 is a number 1 card, the game proceeds to step 114 where the display screen displays a video file corresponding to letters and/or numbers. At step 115, the card reader detects whether any card has been entered. If no card is inserted, the game goes to step 114. If there is an inserted card, the card reader reads the card and displays the card's letters or numbers on the display screen at step 116. The game then checks whether the inserted card is correct, step 117. If the card is incorrect, then the game goes to step 114. If the card is correct, the game displays the video file corresponding to the correct input, step 118. Then, in step 119, the game asks the user if he wants to end the game, and if so, the game goes to step 102; if not, the game proceeds to step 120 where a video file corresponding to another letter and/or number is displayed, and then to step 115.

If the card detected at step 104 is not card number 1, the game passes to step 105 to check if the inserted card is card number 2. If not, the game goes to step 107 and displays "card input is incorrect". If it is a number 2 card, the game proceeds to step 106 where the photograph and/or video file of game 2 is displayed. The card reader then detects whether any plastic card of the present invention is inserted at step 108. If no card is inserted, the reader repeats the detection of step 108. If a card is detected, the game goes to step 109 where the card reader reads the card and displays the card letter or number on the display. The game then checks whether the entered card is correct at step 110. If the card is incorrect, then the game goes to step 108. If the card is correct, the game displays a video file corresponding to the correct input, step 111. Then, in step 112, the game asks the user if he wants to end the game, and if so, the game goes to step 102; if not, the game moves to step 113 to prepare to display another video file corresponding to letters and/or numbers, and then to step 108.

According to the present invention, a method of reading an identification code pattern formed on a surface of an article such as a plastic card includes the steps of: providing an identification code pattern on the code area of the first surface, the identification code pattern comprising a plurality of recesses, through holes and/or protrusions formed on said code area; emitting light rays toward the encoded region such that a portion of the light rays are reflected from the encoded region; receiving the reflected light to read out the identification code pattern according to the amount of the reflected light of each of the plurality of recesses, through holes and/or protrusions; and displaying the corresponding relation between the identification code pattern and the first surface or the second surface.

In summary, the present invention has provided a new technique for identifying a surface that has the advantages of less error and less labor intensity. While the embodiments described herein are provided as examples of surface identification systems and related devices, those skilled in the art will recognize that the present invention should not be limited to the embodiments described above. A person skilled in the art will envision many other possible variations and modifications by incorporating common general knowledge without departing from the scope of the invention, however, such variations and modifications should fall within the scope of the invention.

Claims (20)

1. A surface identification system comprising:

at least one identification code pattern comprising a plurality of recesses, through holes and/or protrusions formed on a code area of a first surface, the identification code pattern being configured to correspond to the first surface or a second surface; and

a code reading device for reading the identification code pattern, the code reading device being capable of emitting light to the code area, receiving reflected light reflected from the code area to read out the identification code pattern according to modulation of an electrical signal corresponding to the amount of reflected light of each of the plurality of recesses, through-holes, and/or projections, and displaying a correspondence between the identification code pattern and the first surface or the second surface,

wherein the modulation is caused by a distance between the code reading device and each of the plurality of recesses, through holes, and/or projections and a light reflection property of a surface of each of the plurality of recesses, through holes, and/or projections.

2. Surface identification system according to claim 1, characterized in that the recesses, through-holes and/or protrusions

Are rectangular and are arranged parallel to each other.

3. The surface identification system of claim 1, wherein the identification code pattern is used to identify information related to features of the surface.

4. The surface identification system of claim 3, wherein the information is selected from the group consisting of: materials, colors, orientations, graphics, numbers, and words.

5. The surface identification system of claim 3, wherein the information is identified according to a coding algorithm.

6. The surface identification system of claim 1, wherein the encoded region is disposed on an edge of the first surface.

7. The surface identification system of claim 1, wherein the code reading device is an infrared optical coupler.

8. The surface identification system of claim 1, wherein each of the plurality of recesses, through holes and/or protrusions represents a binary code "1" or "0".

9. The surface identification system of claim 1, wherein the identification code pattern includes a start bit and an end bit.

10. A method for identifying a surface, the method comprising:

providing an identification code pattern on a code area of a first surface, the identification code pattern comprising a plurality of recesses, through holes and/or protrusions formed on the code area;

emitting light rays toward the encoded region such that a portion of the light rays are reflected from the encoded region;

receiving the reflected light to read out the identification code pattern according to a modulation of an electrical signal corresponding to an amount of reflected light of each of the plurality of recesses, through holes, and/or projections, wherein the modulation is generated by a distance between the code reading device and each of the plurality of recesses, through holes, and/or projections and a light reflection property of a surface of each of the plurality of recesses, through holes, and/or projections; and

and displaying the corresponding relation between the identification code pattern and the first surface or a second surface.

11. Method according to claim 10, characterized in that the recesses, through-holes and/or projections are rectangular and arranged parallel to each other.

12. The method of claim 10, wherein the identification code pattern is used to identify information related to features of the surface.

13. The method of claim 12, wherein the information is selected from the group consisting of: materials, colors, orientations, graphics, numbers, and words.

14. The method of claim 12, wherein the information is identified according to a coding algorithm.

15. The method of claim 10, wherein the encoded region is disposed on an edge of the first surface.

16. The method of claim 10, wherein the light is infrared light.

17. The method of claim 10, wherein each of the plurality of recesses, vias and/or protrusions represents a binary code "1" or "0".

18. A code reading device for reading an identification code pattern on an article, wherein the article has at least one surface comprising a code area in which at least one of the identification code patterns is formed, the identification code pattern comprising a plurality of recesses, through holes and/or protrusions, and the identification code pattern being configured to correspond to the at least one surface or other surface, the code reading device comprising:

a housing;

a power source;

a circuit electrically connected to a power source;

a device for emitting light and detecting the amount of reflected light, said device being operatively connected to said circuit;

at least one channel mounted on said housing for guiding movement of said article such that said emitting and detecting means scans said code area;

at least one holder connected to the at least one channel to receive the item;

wherein the emitting and detecting device is capable of emitting light towards the code area, receiving and detecting reflected light reflected from the code area, transmitting a signal to the electrical circuit for further processing, thereby reading out the identification code pattern representing a correspondence with a surface, in dependence on a modulation of an electrical signal corresponding to the amount of reflected light for each of the plurality of recesses, through holes and/or protrusions,

wherein the modulation is caused by the distance between the emitting and detecting device and each of the plurality of recesses, through holes and/or protrusions and the light reflecting properties of the surface of each of the plurality of recesses, through holes and/or protrusions.

19. The code reading apparatus of claim 18 wherein the transmitting and detecting device is an infrared optocoupler.

20. The code reading device of claim 18, wherein a cover is provided on the housing of the code reading device.