FR2716031A1 - Cyclic image display method using LEDs - Google Patents

Abstract

The method involves forming points on a matrix with rows and columns which correspond to a representation of a displayed, fixed image (4). The columns of the matrix or certain columns make the image appear cyclically to a moving or stationary observer (1) within a short time period, using the property of retinal image remanence. The display unit consists of a vertical alignment of luminous elements equal in number to the lines in the matrix. A control unit consists of a modifiable and interchangeable memory which contains preprogrammed addresses for the points on the matrix. The address information for an image is read and transmitted at a controllable speed to the display where luminous elements corresponding to the image are successively and chronologically displayed.

Description

IMAGE DISPLAY METHOD AND DEVICE
The present invention relates to the method and to the device for implementing this method, allowing an observer to visualize an image next to a vertical alignment of light elements, for a very short time during the movement of his gaze. in the visual field of action of these light elements.

 Most known systems display images on a surface area equivalent in size to the images.

The invention makes it possible to display an image from a column of luminous points, and this for a very brief instant, which creates an effect of astonishment on the observer.

Indeed, if an observer looks at this column in a fixed way, he will only see a luminous column. On the other hand, if he dismisses his gaze, when he directs him again towards this luminous column, he will very briefly see an image appear next to this column. This optical effect is particularly attractive, decorative and interesting.

 According to the invention, there is in particular proposed a method for displaying images, characterized in that it consists in composing a dot matrix of (L) rows and (C) columns corresponding to the drawing of an image to display, to display in a geographically fixed place, successively and chronologically in a time t, all the columns of this matrix, or some of these columns, in a cyclic fashion, to make this image appear to a motionless or moving observer, during a very short duration of the scanning of its gaze towards the place where the columns are displayed, using the retentivity characteristic of the retina of the eye.

 Indeed, when the elements constituting the retina of the eye capture light information 'it' at the instant 'tl', they keep this light information 'it' until the instant 't2', phenomenon known in itself and called "persistence or remanence of the retina", on which the cinema is based. If before time 't2', light information 'i2' is received, the retina will keep at least until time 't2' the two light information 'il' and 'i2' simultaneously. If in addition, before the instant 't2', the eye has moved, the retina will keep these two pieces of light information 'il' and 'i2', but this time, shifted in position one relative to the other, in proportion to the displacement of the eye.

An observer, motionless or in motion, moving his gaze horizontally towards the place where the columns are displayed, will successively print and keep on the retina of his eyes the columns composing the drawing. Each displayed column prints on the retina of its eyes, horizontally shifted in position relative to the previously displayed column. This horizontal position offset is proportional to the speed of movement of his gaze and to the time interval between the display of two consecutive columns. This observer will then see the representative image of the drawing appear, reconstructed on the retina of his eyes, next to the place where all the columns were displayed.

 According to the invention there is also proposed an image display device implementing this method characterized in that it comprises a display unit consisting of a vertical alignment of (L) light elements equal in number to that lines of the dot matrix representative of the design of the image to be displayed and of circuits for operating them, a control unit consisting of a memory, modifiable and interchangeable, in which are preprogrammed at known addresses the information of the dot matrix representative of the drawing of 1 image to be displayed, and of circuits making it possible to read the information in the memory and transmit it at an adjustable speed to the display unit in order to select the corresponding light elements so that successively and chronologically displays all the columns of the matrix. The memory can contain information relating to several drawings of images to be displayed.

The present invention will be better understood and other characteristics will appear with the aid of the description below and of the figures relating thereto which represent
FIG. 1, a diagram intended to illustrate the method according to the invention,
- Figure 2, a diagram of a dot matrix,
FIG. 3, a diagram of a display device,
FIG. 4, a diagram of the control part of the device,
- Figure 5, a diagram of the display part of the device.

 In the various figures, the corresponding elements are designated by the same references. In the various electronic diagrams, the precise synchronization devices, which are part of current technology, have not been shown in order to make the drawings clearer and to simplify the description.

Figure 1 is a diagram illustrating the method according to the invention
The observer (1) moving his gaze (2) from left to right towards the device (3) for implementing the process, sees for a very short time the drawing (4) next to the device (3).

 FIG. 2 represents the constitution of a dot matrix of (L) rows and (C) columns.

Figure 3 shows the block diagram of this device without limitation
This device consists of a control unit (5) and a display unit (6). The display unit (6) is a column of light points, in particular light-emitting diodes, having very short on and off times compared with other types of light elements. The selective lighting of these diodes, controlled by the control unit (5), makes it possible to reconstruct successively on this column of light points the different columns making up the drawing representative of the image to be displayed. A clock signal (CLK) generated by the control unit (5) is transmitted to the display unit (6). The display unit (6) generates a signal (DISP) at the end of each column display cycle.

Figure 4 shows the block diagram of the control unit
The control unit is composed of a clock circuit (8), an address counter (9), a memory (11) and a counter management circuit (12). The clock circuit (8) generates a regular and adjustable clock signal (CLK) driving the address counter (9). This address counter (9) is initialized at address "0" when the device is powered up and is incremented by one at each pulse of the clock signal (CLK). These addresses are transmitted to the memory (11) via the address bus (10).

When the memory (11) receives an address on its address entries, it reads the content of the memory location corresponding to this address and transmits it to the display unit via the data bus (7) . The counter management circuit (12) is used to allow a user of this device to set the number of repetitions of the display cycle of a drawing, in the case where the memory contains several drawings. This counter management circuit (12) counts the number of pulses received by the signal (DISP), each pulse corresponding to the display of a column by the display unit. At the first pulse of the display cycle of a drawing, it stores the address on the address bus in a buffer register, as the address for the start of the display cycle of this drawing. When this counter management circuit (12) has received (C) pulses, it will reposition the counter (9) at the stored cycle start address of the drawing to be displayed, in order to renew the display of the same drawing, and this a number of times x, adjustable by the user. Upon the pulse of the clock signal (CLK) according to the x repetitions of the display cycle, the counter management circuit stores the address on the address bus (10), considering it as new. cycle start address for the next drawing which is also displayed x times. This process is repeated until the last drawing, then a reset of the counter (9) is carried out in order to renew the display of all the drawings. This counter management circuit is used in an embodiment of the device intended to display several drawings. Being easily achievable with current circuits in electronics and in order not to burden the description, this circuit is not more detailed.

Figure 5 illustrates the operation of the display unit
The display unit consists of a shift register (16) of series-parallel type and of a number "n" of display blocks, all identical, referenced (13) for the first, (14) for the second and (15) for the umpteenth.

Each display unit consists of two identical registrestampon (17) and (18) and a set (19) of eight light elements (20). The eight data outputs of the buffer register (17) are respectively connected to the eight data inputs of the buffer register (18) via a bus (21). The eight data outputs of the buffer register (18) are respectively connected to the eight light elements (20). The data bus (7) is connected to the eight inputs of the buffer register (17) of all faceplates.

The shift register (16) includes 1, n + 1 "outputs. The clock signal (CLK) from the clock circuit (8) of the control unit is connected to the clock input of the register The first output of the shift register (16) is connected to the validation input (CE1) of the buffer register (17) of the first display block (13), the second output of the register to shift (16) is connected to the validation input (CE1) of the buffer register (17) of the second display block (14), and so on, up to the umpteenth output of the shift register (16) which is connected to the validation input (CE1) of the buffer register (17) of the umpteenth display block (15). The (n + l) th output of the shift register (16) is connected to the input validation (CE2) of the buffer register (18) of all the display blocks. The clock signal (CLK) is also connected to the clock input of all the buffer registers, this not being represented s for more clarity in Figure 5. At each pulse of the clock signal (CLK), the buffer registers used memorize the eight data present on their eight data inputs. These eight data are transferred to the eight data outputs of the buffer register as soon as its validation input (CE) receives a signal passing from logic level "0" to logic level "1", hereinafter called "rising edge", and will remain present until the reception of a new rising edge. When the device is powered up, all signals are set to logic level "0".

 In this spirit, during the first pulse of the clock signal (CLK), the data read at the first address of the memory is present on the eight data inputs of the buffer register (17) of all the display blocks . At this same moment, the first output of the shift register (16) goes from logic level "o" to logic level "1", thus sending a rising edge to the validation input (CE1) of the buffer register (17) of the first display unit (13). This first data is therefore transferred to the data outputs of this buffer register (17), thus being present on the data inputs of the buffer register (18) and memorized until receipt of a rising edge on its input. validation (CE2). By the same process, during the second pulse of the clock signal (CLK), the data located at the second address of the memory will be kept in the buffer register (18) of the second display block (15), and so on, during the umpteenth pulse of the clock signal (CLK), the data located at the umpteenth address of the memory will be kept in the buffer register (18) of the umpteenth display block (15). During the (n + l) th pulse of the clock signal (CLK), the (n + l) th output of the shift register (16) will pass from logic level "0" to logic level "1", sending a rising edge on the validation input (CE2) of the buffer register (18) of all faceplates. Thus, the "n" data stored in the "n" buffer registers (18), corresponding to the first column of the matrix, will be simultaneously transferred to their respective "n" sets (19) of light elements (20). Likewise, the (n + 1) th output of the shift register (16) will send a rising edge to its reset input (RST), thereby putting all of its outputs back to logic level "0". The first column making up the matrix will therefore be displayed. This cycle will repeat until the last memory address in the data area of the first drawing in order to successively display the "n" columns of this drawing.

 It should be noted that in the example according to FIG. 1, the observer (1) can be in motion.

 It should also be noted that in the example according to FIG. 5, the light elements (20) may consist of light-emitting diodes emitting different colors in order to display color images.

 The present invention is not limited to the examples described.

Claims (6)

 1) Image display method characterized in that it consists in composing a dot matrix of (L) rows and (C) columns corresponding to the drawing of an image (4) to be displayed, to be displayed in a place geographically fixed, successively and chronologically in a time t, all the columns of this matrix, or some of these columns, in a cyclic manner, to make this image (4) appear to an observer (1) stationary or in motion, during a very short duration of the scanning of its gaze (2) towards the place where the columns are displayed, using the remanence characteristic of the retina of the eye.  2) Method according to claim 1 characterized in that an image is reconstructed on the retina of the eyes of an observer stationary or in motion by the combination of the displacement of his gaze and the persistence of the retina of his eyes.  3) Image display device characterized in that it comprises a display unit (6) consisting of a vertical alignment of (L) light elements (20) equal in number to that of the rows of the matrix to points representative of the design of the image to be displayed and of circuits for operating them, a control unit (5) consisting of a memory (11), modifiable and interchangeable, in which the information of the information is preprogrammed at known addresses dot matrix representative of the design of the image to be displayed, and of circuits making it possible to read the information in the memory (11) and transmit it at an adjustable speed to the display unit (6) in order to select the corresponding light elements (20) so that all the columns of the matrix are displayed successively and chronologically.  4) Device according to the preceding claim characterized in that the memory (11) can contain information relating to several drawings of images to be displayed.  5) Device according to claims 3 and 4 characterized in that each light element (20) consists of a set of light emitting diodes emitting identical or different colors. In order to display color images.  6) Device according to claims 3,4 and 5 characterized in that the number of repetition of the display cycle of a design is adjustable.