JPH0753157B2 - Accelerometer - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acceleration plethysmometer used for health check in health care rooms, training centers and the like.

2. Description of the Related Art Conventionally, as an acceleration plethysmometer of this type, there is known an acceleration plethysmometer by adding two differentiators to a so-called finger plethysmography by photoelectric conversion method.

The problem to be solved by the invention However, in this conventional device, the amount of light emission at the blood flow pickup unit is constant, and when the power of the main body of the pulse wave meter is turned on, light emission starts at that point and the power is turned off. The lamp is always turned on even during non-measurement until it is measured. Therefore, since the tungsten lamp is used as the light emitting element, the life of the light emitting element is remarkably reduced, the blood flow pickup must be frequently replaced, and energy loss is large.

The present invention solves such a problem by detecting from the output of the light receiving element whether or not there is a fingertip of the person being measured in the blood flow pickup, and when there is no fingertip, the lighting of the light emitting element is stopped, or This is to limit the amount of light emission.

Means for Solving the Problems In order to solve this problem, the present invention provides a blood flow pickup that detects an increase or decrease in blood volume at a fingertip by a photoelectric conversion method using a light emitting element and a light receiving element, and the blood flow pickup. An acceleration pulse wave converter that second-order differentiates the output waveform detected by the pulse wave, that is, a pulse wave, to an acceleration pulse wave, and the presence or absence of a fingertip in the blood flow pickup is detected based on the output of the blood flow pickup. When it is detected that the light emitting element does not exist, the light emitting element controller is provided to stop the lighting of the light emitting element or to control the light emitting quantity.

Operation With this configuration, the light-emitting element is turned off when not measuring,
Alternatively, it becomes possible to limit the amount of light emission, so that not only the life of the light emitting element can be extended but also energy loss can be eliminated.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. In FIG. 1, 1 is a blood flow pickup,
The light emitting element 2 and the light receiving element 3 are built in, and an increase / decrease in blood flow at the fingertip 9 is detected by a photoelectric conversion method. The light emitting element 2 is a tungsten lamp or the like.
Reference numeral 4 denotes an acceleration pulse wave converter connected to the blood flow pickup 1, which converts a pulse wave detected by a pulse wave detecting section 5 incorporated therein into an acceleration pulse wave by a secondary differentiating section 6. Reference numeral 7 is a CRT that outputs the acceleration pulse wave waveform obtained by the acceleration pulse wave converter 4 as an image. Reference numeral 8 denotes a light emission amount controller, which detects whether or not the fingertip 9 is inserted in the blood flow pickup 1 based on the output of the blood flow pickup 1, and when it is detected that the fingertip is not inserted, It has a function of stopping lighting of the light emitting element 2 or limiting the amount of light emission.

FIG. 2 is an explanatory diagram showing the difference in the amount of light received by the light receiving element 3 during measurement A and during measurement B.

The operation in the above configuration will be described. When the measurement subject inserts the fingertip 9 into the blood flow pickup 1, the light emitted from the light emitting element 2 passes through the fingertip 9 of the measurement subject and is received by the light receiving element 3. The fluctuation of the amount is detected by the pulse wave detector 5 in the acceleration pulse wave converter 4. After that, it is converted into an acceleration pulse wave in the secondary differentiator 6, and the waveform is displayed on the CRT 7 as an image. The amount of light received by the light-receiving element 3 at this point depends on the fluctuation of the blood flow in a state where the amount of light received is significantly reduced as a whole because the light is blocked by the fingertip 9 as shown by A during measurement in FIG. It has become clear that it shows different changes. Next, when the person to be measured finishes the measurement and pulls out the fingertip 9 from the blood flow pickup 1, there is nothing that blocks the light of the light emitting element 2, so the amount of light received by the light receiving element 3 increases rapidly as shown by B in the figure. To do. Therefore, the light emission amount controller 8 detects that the fingertip 9 is pulled out from the blood flow pickup 1 due to this change, and immediately the light emitting element 2
It is possible to stop or limit energization to the. At the time of reuse, it is automatically detected by detecting that the light receiving amount of the light receiving element 3 is further reduced by separately starting the energization of the light emitting element 2 or inserting the fingertip 9 into the blood flow pickup 1. It is for normal use.

As described above, according to the present invention, the light emitting element is automatically turned on when the person to be measured finishes measuring the acceleration pulse wave by increasing or decreasing the amount of light received by the light receiving element without using a special sensor. Because it can be stopped or the amount of light emission can be limited,
With a simple structure, the life of a light emitting element such as a tungsten lamp can be significantly extended. Furthermore, it is possible to reduce energy loss during non-measurement by stopping or limiting the current of the lamp part that consumes much more current than the circuit part made of semiconductor etc. when not in use. It is extremely useful.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG.
The drawings are explanatory views for facilitating the understanding of the present invention. 1 ... Blood flow pickup, 2 ... Light emitting element, 3 ... Light receiving element, 4 ... Acceleration pulse wave converter, 8 ... Emission amount controller.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuji Hattori 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Haruo Terai, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 72) Inventor Taketoshi Sato 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A blood flow pickup for detecting an increase / decrease in blood volume at a fingertip by a photoelectric conversion method using a light emitting element and a light receiving element, and a second derivative of an output waveform detected by the blood flow pickup, that is, a pulse wave. An acceleration pulse wave converter for converting into an acceleration pulse wave, and the presence or absence of a fingertip in the blood flow pickup is detected based on the output of the blood flow pickup, and when the absence of the fingertip is detected, the lighting of the light emitting element is stopped. Or an acceleration plethysmometer including a light emission amount controller for controlling so as to limit the light emission amount.